Syntactic complexity has received a great deal of attention in the literature on second language writing. Relative clauses, which function as a kind of noun phrase post-modifier, are among those structures that are believed to contribute to the complexity of academic prose. These grammatical structures can pose difficulties for EFL writers even at higher levels of proficiency, and it is therefore important to determine the frequency and accuracy with which relative clauses are used by L2 learners since understanding learners’ strengths and weaknesses in using these structures can inform teachers on ways to improve the process of their instruction in the writing classroom. This paper reports on a corpus-based comparison of relative clauses in a number of argumentative essays written by native and non-native speakers of English. To this end, 30 argumentative essays were randomly selected from the Persian sub-corpus of the ICLE and the essays were analyzed with respect to the relative clauses found in them. The results were then compared to a comparable corpus of essays by native speakers. Different dimensions regarding the structure of relative clauses were investigated. The type of relative clause (restrictive/non-restrictive), the relativizer (adverbial/pronoun), the gap (subject/non-subject), and head nouns (both animate and non-animate) in our two sets of data were manually identified and coded. The findings revealed that the non-native writers tended to use a greater number of relative clauses compared to their native-speaker counterparts.

中文翻译：

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EFL学习者在议论文中对从句的考察

在第二语言写作的文献中，句法复杂性受到了广泛的关注。相对从句作为一种名词短语后修饰词，被认为是造成学术散文复杂性的结构之一。这些语法结构即使在熟练程度较高的情况下也可能给EFL写作者带来困难，因此，重要的是确定第二语言学习者使用相对从句的频率和准确性，因为了解学习者在使用这些结构时的优势和劣势可以告知教师在写作课堂上改善他们的教学过程的方法。本文报告了基于语料库的由英语为母语和非母语的人在许多论证性文章中对相对从句的比较。为此，从ICLE的波斯子语料库中随机抽取30篇论据，并对其中的相关从句进行分析。然后将结果与以母语为母语的人比较的论文集进行比较。研究了有关从句结构的不同维度。我们两组数据中的相对从句（限制性/非限制性），相对词（副词/代词），差距（主语/非主语）和首名词（有生命和无生命）的类型都是手动的确定并编码。调查结果表明，与母语人士相比，非母语作家倾向于使用更多的相对从句。