A corpus-based study of the English synonyms assure, ensure, and guarantee

Due to the abundance of synonyms in the English language, English learners struggle to identify the specific contextual usage, resulting in not being fully aware of the authentic use of certain synonyms. The purposes of this study were to explore the similarities and differences of three synonymous verbs assure, ensure, and guarantee based on the distribution across genres in relation to degree of formality and to examine their object-noun and adverb collocates in terms of semantic preference. Data were drawn from Corpus of Contemporary American English (COCA) with additional references from the Longman Dictionary of Contemporary English (LDOCE) Online. The findings of this study illustrate that ensure has the highest occurrences and is preferable in formal contexts, whereas assure and guarantee frequently occur in informal contexts. Regarding the typical object-noun and adverb collocates, the top thirty collocates of each target synonym with significant value of MI score ≥ 3 were listed and the semantic preferences of collocates with similar meanings were categorized into themes. It was discovered that the collocates of the target synonyms share overlapping themes but still have their respective unique themes signifying their specific contextual usage. This demonstrates that, despite the target synonyms having the same core meaning, they are near-synonyms, as they cannot substitute for one another in all contexts.