1. Introduction

The issue of determining the equivalence and non-equivalence of grammatical structures in different languages is considered to be one of the key branches of comparative grammar research. Comparing the English and Tajik languages from this perspective demonstrates that the method of forming complex sentences, the syntactic relations between their components, and the grammatical connections within this linguistic unit are not identical in the languages under comparison. Such differences have a serious impact on the way clauses are linked, the correlation between form and meaning, and the choice of connective means. Observation and comparison of complex sentences in the two languages reveal that many logical relations (time, condition, cause, conclusion, comparison) do not transfer directly from one language to another. Therefore, the problem of equivalence is specifically related to the level of syntax, particularly complex sentences (complex, compound, compound-complex sentences).

Comparative research between the structures of English and Tajik has mainly focused on the study of individual components: for example, verb forms, the complex infinitive, adverbs, conjunctions, and so on. The works of researchers — F. Zikriyoyev, M. Qosimova, K. Usmonov, P. Jamshedov, B. Niyozmuhammadov, as well as foreign scholars V.D. Arakin, N. Teshaboyeva and U. Bosimova — have contributed to clarifying the essence of syntactic relations.

However, the issue of formal equivalence and non-equivalence at the level of complex sentences, particularly in comparing English and Tajik, has not been extensively or directly studied to date. This gap, on the one hand, underscores the necessity of research and, on the other hand, calls for the creation of a precise methodology. Therefore, addressing this issue within the scope of investigation will undoubtedly help unravel the related problems.

The purpose of the article is to identify and analyze instances of formal grammatical equivalence and non-equivalence in the complex sentences of the English and Tajik languages, focusing on the syntactic, functional, and semantic challenges that arise in comparative analysis and translation between these two linguistically distinct systems.

The genesis of the article stems from the observed gap in existing comparative linguistic studies, which have primarily focused on individual grammatical elements (e.g., verb forms, adverbs, conjunctions) rather than systematically addressing the structural and functional mismatches at the level of complex sentence formation.

The functions of the article are threefold: first, to systematically describe the key areas of formal non-equivalence between English and Tajik complex sentences, including non-finite verb forms, tense agreement, and the multifunctional conjunction ki; second, to demonstrate, through the analysis of factual linguistic material (including literary translations), how functional equivalence is achieved despite formal divergence; and third, to contribute to the development of a more precise methodology for the comparative study of syntax in typologically different languages.

2. Materials and methods

The material for this study consists of complex sentences extracted from the literary works of Sadriddin Ayni, specifically from “Qahramoni xalqi tojik Temurmalik. Isyoni Muqanna” (The Tajik People’s Hero Temurmalik. The Revolt of Muqanna’), as presented in a bilingual edition (Tajik original with English translation by Professor Abdusalam Mamadnazarov) [1]. The analysis is comparative and qualitative in nature. The primary method employed is contrastive syntactic analysis, involving the identification of complex sentence structures (compound, complex, and compound-complex) in the source text (Tajik) and the comparison of their formal and functional properties with their target language equivalents (English). The study examines grammatical relations, the means of clause linkage (conjunctions, relative pronouns, non-finite forms, intonation), and the transformations applied during translation to achieve equivalence.

3. Main results and discussion

Complex sentences are among the most important grammatical units, consisting of two or more simple clauses between which there are relations of subordination or coordination. Theoretical and practical research on the structure of complex sentences in modern linguistics has been carried out by a number of scholars.

Seemingly, one can cite the doctoral dissertation of M. Abdurahmonova, who recently conducted valuable research on the polysemy of subordinate clauses in the modern Tajik literary language [2]. The researcher justifies the choice of this topic as follows: “An in-depth and comprehensive study of the structural and semantic features of Tajik grammar and the evolution of its structure is very important from the perspective that it reveals trends in slow and initially imperceptible changes, helping to identify periods of language formation. The literary prose of each period is an indicator of changes appearing in the language, and it is precisely through the analysis of the text of literary prose that observed language changes can be substantiated as factual phenomena or, conversely, proven to be unfounded” [2, P. 4]. Indeed, the transformation of any language's structures is connected to such grammatical factors, making the discovery of such developments highly significant and timely.

In Sh. Rustamov’s book, the conjunction чун (chun) is cited as evidence, and based on factual material, it is proven to have three functions:

a) indicating the time of the main clause's occurrence (time);

b) indicating the reason for the main clause's action (cause);

c) indicating the condition upon which the execution of the main clause's action depends (condition).

The researcher believes that in connecting the main clause and an adverbial clause of reason, the conjunctions зеро (zero), зеро ки (zero ki), чунки (chunki), азбаски (azbaski), бинобар он ки (binobar on ki), бинобар ин ки (binobar in ki), аз сабаби ин ки (az sababi in ki), ба сабаби ин ки (ba sababi in ki), ба сабаби он ки (ba sababi on ki), чаро ки (charo ki), ин ки (in ki), and он ки (on ki) play a prominent role [12, P. 124].

M.N. Qosimova, in the second and third chapters of her dissertation dedicated to the conditional subordinate clause, provides detailed information about the subordinating conjunctions агар (agar), ки (ki), то (to), агар ки (agar ki), ба шарте ки (ba šarte ki), вақте ки (vaqte ki), ҳар гоҳ ки (har goh ki), модоме ки (modome ki), чун (chun), кошки (koški), магар ки (magar ki), and others [10, P. 23]. Examples of the available conjunctions in the modern Tajik literary language demonstrate that the element ки (ki) is grammatical, serving only a subordinating function in complex subordinate sentences and linking all types of subordinate clauses to the main clause.

F. Zikriyoyev, in two subsections entitled “Subordinate Clauses of Manner and Comparison in the Modern Tajik Literary Language,” addresses the grammatical means of connection for subordinate clauses of manner and comparison. According to the author, the specific conjunctions for subordinate clauses of manner are primarily the subordinating conjunctions дар ҳолате ки (dar holate ki), дар ҳоле ки (dar hole ki), ба ҳолате ки (ba holate ki), дар вазъияте ки (dar vaz'iyate ki), дар сурате ки (dar surate ki), ба тартибе ки (ba tartibe ki), ба тарзе ки (ba tarze ki), бе он ки (be on ki), and бе ин ки (be in ki). These not only serve as grammatical means but also retain some of their lexical meaning, playing a significant role in clarifying the semantic relationship between the main and subordinate clauses [8, P. 42].

In the monograph, the compound conjunctions (ба) монанди он (ин) ки ((ba) monandi on (in) ki), (ба) мисли он (ин) ки ((ba) misli on (in) ki), чунон ки (čunon ki), чӣ (ба) тавре ки (čī (ba) tavre ki), ба (чӣ) тарзе ки (ba (čī) tarze ki), чӣ хеле ки (čī hele ki), ончунон ки (ončunon ki), ҳамчунон ки (hamčunon ki), ба тартибе ки (ba tartibe ki) are presented as conjunctions of comparative subordinate clauses. It is emphasized that most of these are functionally equivalent and synonymous, capable of replacing one another. The salient feature of this type of conjunction is discussed by Professor F. Zikriyoyev as follows: “What is characteristic of this group of comparative-contrastive conjunctions is that all of them are considered meaningful conjunctions: it is clear from the semantic meaning they retain that they convey the concept of comparison, comparing different events, processes, objects, actions, and states with other similar real objects, actions, and processes” [8, P. 91].

Another researcher, B. Rahimzoda, also made a significant contribution to the analysis of the structure and meaning of complex sentences, explaining the issues of logical-semantic relations and the formation of subordinate clauses in his book Syntax of the Tajik Language [11, P. 90].

In the field of comparative grammar regarding the equivalence of complex sentence structure in Tajik and English, the work of P. Jamshedov is worthy of attention. In his work A Comparative Grammar of Tajik and English, he analyzes the formal equivalence of complex sentences and the semantic equivalence of complex clauses in a comparative manner [6, P. 210].

In Russian linguistics, the research of A.M. Peshkovsky and V.V. Vinogradov laid the theoretical foundation for the study of subordination and coordination relations in complex sentences. In his work Russian Syntax in Scientific Light, Peshkovsky analyzes the external and internal relations of the components of a complex sentence [13, P. 278], while V.V. Vinogradov examines the semantic relations between the parts of a complex sentence [5, P. 315].

In English linguistics, the research of Otto Jespersen holds a special place. His work A Modern English Grammar on Historical Principles is one of the most detailed sources on complex sentences [14].

Furthermore, in modern grammar, the work by N. Teshaboyeva & U. Bosimova presents a structural and functional analysis of subordinate clauses [15, P. 190–193].

In comparative linguistics, equivalence encompasses not only semantic correspondence but also the correspondence of grammatical functions. It should be noted that although the Tajik language was inflectional during the ancient and middle periods of Iranian language development, under the influence of internal and external linguistic factors, it has shown a tendency towards analyticity in the modern period. Observation of the grammatical features of English shows that this language also possesses the characteristics of an analytic structure. However, observation of evidence reveals that despite the similar structure of the two languages being compared, differentiating features are perceived in them.

First and foremost, such a difference can be observed in the features of equivalence and non-equivalence of individual elements of these two languages.

This is one of the primary areas where "different" elements arise. In English, the Infinitive, Gerund, and Participle can act as substitutes for subordinate clauses. To prove this point, consider the following example: I’m looking forward to meeting you. – Tajik: Ман мунтазири вохӯрӣ бо шумо ҳастам (Man muntaziri voxūrī bo šumo hastam — "I am waiting for the meeting with you"). If this were expressed as “Ман мунтазирам, ки бо шумо вохӯрам” (Man muntaziram, ki bo šumo voxūram — "I am waiting that I meet you"), it would represent a complex subordinate clause.

According to V.D. Arakin, the non-finite structures of English are often expressed in other languages through full subordinate clauses or lexical units, which is a sign of morphological non-equivalence [3, P. 154].

In English complex subordinate sentences, there is a strict rule of sequence of tenses. This grammatical element does not exist in Tajik, leading to "functional non-equivalence": She said that she was busy (Past Simple in the subordinate clause to express relative present tense). In Tajik: Ӯ гуфт, ки банд аст (Ū guft, ki band ast — "She said that busy is").

Linguist L.S. Barkhudarov notes that when translating complex sentences, equivalence is maintained at the level of content but changes at the level of form, because the category of tense has its own logic in each language [4, P. 92].

In Tajik, the conjunction ки (ki) is multifunctional and can perform the function of dozens of English conjunctions and relative pronouns (e.g., who, which, that, because, when, so that). This can be termed "multifunctional equivalence."

P. Jamshedov shows in his research that the universalism of the conjunction ки (ki) in Tajik is one of the main grammatical differences compared to Germanic languages [6, P. 118].

A common feature of Tajik and English is that their sentences are divided into simple and complex types. In speech, for artistic coloring, both types of complex sentences are used. Through these sentences, relatively interdependent and complete thoughts are expressed.

The sentence is the main predicative and communicative unit of speech, expressed in various forms and patterns. Their basis is formed by simple sentences. However, the needs of human thought create new patterns of speech in language, which consist of a set of simple sentences with specific semantic and grammatical relations between them. A sentence composed of two or more simple clauses, unified in meaning and intonation, is called a complex sentence [9, P. 101].

Example (Tajik): “Ривоҷи чорводории ин сарзаминҳоро аз ҳамин қиёс кардан мумкин аст, ки танҳо чарогоҳҳои кўҳистони Ҳисор, ки дар он вақтҳо он ҷо Чағониён номида мешуд, ҳарсола ба тариқи андоз... 24 ҳазор гўсфанди ҳисорӣ медод”. English Translation: “The development of the animal husbandry can be judged from the statistic that just the pastures of the Gissar Mountains — called Chaghaniyan at that time — provided the kitchen of Seljuk Sultan Sanjar 24,000 sheep every year as a tax” [1, P. 12].

In the original Tajik text, we see a complex subordinate structure with two subordinate clauses, both introduced by the conjunction ки (ki). During translation, the translator converted the second subordinate clause (“ки дар он вақтҳо он ҷо Чағониён номида мешуд” — “which at that time was called Chaghaniyan”) into a non-finite attributive phrase (“called Chaghaniyan at that time”). This is a sign of formal non-equivalence. In English, using parenthetical phrases between dashes is smoother and more common than sequential subordinate clauses. In the original sentence, the predicate verb (“медод” — “provided”) is at the very end of the sentence, characteristic of Tajik (Subject-Object-Verb order). In the translation, the verb “provided” comes immediately after the subject “pastures”. This structural transformation is necessary to adhere to English word order. The word “қиёс” (qiyos) originally means “example” or “analogy”. In the translation, it becomes “statistic”. This transformation strengthens the logic of the sentence in English, as the text refers to a specific number (24,000 sheep). The phrase “ба тариқи андоз” (ba tariqi andoz — “as a tax”) corresponds to “as a tax”, demonstrating full semantic equivalence. The phrase “қиёс кардан мумкин аст” (qiyos kardan mumkin ast — “it is possible to compare/analogize”) is a modal-impersonal construction in Tajik, rendered in English as “can be judged” (passive voice). This method serves to maintain the academic and historical style of the work in both languages.

This example proves that in Tajik complex sentences, the conjunction ки (ki) has a multifunctional role (for both complement and attributive clauses). When translating into English, to avoid grammatical heaviness, one part of the subordinate clauses is often reduced to condensed phrases, which constitutes the essence of formal non-equivalence and functional equivalence.

Example (Tajik): “Дар он вақтҳо ободии Хуҷанд ба ҷойе расида буд, ки вайро “Тирози ҷаҳон”, (зебу зиннати ҷаҳон) мегуфтанд” [1, P. 14]. English Translation: “In those days the development of Khujand reached such a level that people called it “the Tiroz of the world”, that is “the beauty of the world”.

Here we see strong equivalence at the level of grammatical patterns. In the original sentence, the phrase “ба ҷойе расида буд, ки...” (ba joe rasida bud, ki... — “had reached a place/such a level that...”) functions to indicate the degree and result of the action. In the translation, the translator used the equivalent English pattern “reached such a level that...”. This is an example of functional equivalence, where meaning and grammatical function are expressed by equally powerful structures in both languages.

This reveals an important stylistic and grammatical difference in the translation of this sentence: In the original, the verb “мегуфтанд” (meguftand — “they said / people said”) is in the third-person plural, which in Tajik often functions as an impersonal or general-personal clause (i.e., “it was said,” “people said”). In the translation, the translator added the specific subject “people”, converting the sentence into a personal active-voice structure (“people called it”). This transformation is necessary for English, as this language has a greater need for a grammatical subject.

Regarding explanatory phrases: In the original, the phrase “зебу зиннати ҷаҳон” (zebu zinnati jahon — “the beauty/adornment of the world”) appears in parentheses as an explanation of the term “Тирози ҷаҳон” (Tirozi jahon — “the Tiroz/Embroidery of the world”). In the translation, the translator uses the common English phrase “that is” (i.e., meaning “in other words”) to link this explanation. This operation serves the fluency of the English text and makes the Orientalist (Eastern) term more understandable.

The pronoun “вайро” (vayro — “it” referring to Khujand-city) in the Tajik original corresponds to the inanimate pronoun “it” in the translation. This demonstrates morphological equivalence at the syntactic level. This example shows that when translating Tajik complex subordinate sentences that convey result and degree, the translator can find precise structural equivalents (such... that). However, the difference manifests in the fact that Tajik general-personal structures (мегуфтанд — meguftand) are often rendered in English by adding a grammatical subject (people), to avoid violating the grammatical principles of English. Complex sentences are divided according to the semantic relations and grammatical connections between their constituent simple sentences into: compound sentences, complex sentences, and compound-complex sentences [7, P. 165].

There are two types of complex sentences: conjunctional complex sentences, which are formed through intonation and coordinating or subordinating conjunctions.

Example (Tajik): “Ғуломони ҳинду чунон бисёр буданд, ки дар адабиёти он замон ва баъд аз он замон то чандин сад соли дигар “ҳинду” ба маънои ғулом кор фармуда мешуд” [1, P. 30]. English Translation: “The number of Indian slaves was so enormous that in the literature of those years, and for several hundred years after, people used the word “Hindu” as the synonym of the term “slave”.

This is a complex subordinate sentence with a result clause. In English, it is expressed with the conjunction so... that, and in Tajik with the pattern чунон... ки (chunon... ki). The most interesting transformation in this sentence is the shift from the Passive to the Active voice. In the original, Sadriddin Ayni used the passive structure (“кор фармуда мешуд” — kor farmuda mešud — “was used”). In Tajik, this mode of expression serves to emphasize the action itself and the historical situation.

In the translation, the translator converted the structure to the active voice with the generic subject “people” (“people used”). This is a sign of stylistic and grammatical non-equivalence. English prefers active voice constructions over passive for fluency, even if the subject (people) is not explicitly mentioned in the source text.

Expansion/Transformation of the initial clause: The beginning of the original sentence is very simple and condensed: “Ғуломони ҳинду чунон бисёр буданд” (Gulomoni hindu čunon bisor budand — “Indian slaves were so many”). In the translation, the translator expanded the phrase, adding the words “The number of...” and transformed the adjective “бисёр” (bisor — “many”) into “enormous”. This is a lexical-grammatical transformation that serves to express the meaning of “many” more effectively in English.

Functional equivalence of the result pattern: The Tajik pattern чунон... ки (chunon... ki) and the equivalent pattern so... that are used. Here we see complete functional equivalence. Both languages use similar conjunctional structures to express result, demonstrating their typological correspondence in this area. The analysis of this example from the works of Sadriddin Ayni shows that when transforming complex sentences from Tajik into English, the following regularities are observed: grammatical compression — Tajik subordinate clauses often become condensed phrases in English; voice change — Tajik passive constructions are often rendered in English as active (with the addition of people, we, they); functional equivalence — patterns expressing result and degree (чунон... ки and so... that) have precise structural equivalents.

The comparative study of complex sentences in English and Tajik shows that the issue of equivalence is not limited to word-for-word translation but requires a deep adaptation of grammatical structures. English, as an analytic language, and Tajik, with its strong synthetic-analytic features, employ different pathways in forming complex sentences. This leads to instances of "formal non-equivalence," where a grammatical structure in English (e.g., infinitive or participial phrases) is rendered in Tajik by a full subordinate clause.

One of the main syntactic differences manifests in the fact that the subordinating conjunction ки (ki) in Tajik has a multifunctional role, serving as the equivalent for dozens of English conjunctions and relative pronouns (who, which, that, because, when, so that).

The analysis of examples from the works of Sadriddin Ayni proved that during translation from Tajik into English, English "personal-active" structures often transform into Tajik "impersonal-passive" structures. This operation is necessary to maintain the fluency of the text and the stylistic coloring of the Tajik language.

4. Conclusion

Thus, equivalence in complex sentences between English and Tajik is not found in the superficial resemblance of grammatical elements but in the preservation of logical-semantic content, grammatical function, and communicative intent. Formal non-equivalence is the norm, not the exception. Recognizing this allows linguists, translators, and language educators to move beyond a naive expectation of structural isomorphism and instead focus on achieving functional correspondence through principled, predictable transformations. The richness of both languages is fully revealed precisely in those moments where a direct equivalent is absent, and the translator must draw upon the full creative and structural resources of the target language to faithfully render the meaning of the source. This study thus affirms that comparative grammar, at its most productive, is not the search for identical forms but the systematic mapping of divergent pathways to shared communicative goals.

The additional file for this article can be found as follows: