This study aims to analyze nominal and verbal inflection patterns in the oral vocabulary production of learners of English as a Foreign Language (EFL). According to Lieber (2009), Aronoff and Fudeman (2011), Booji (2005), McCarthy (2002), and Haspelmath (2002), there are three primary types of inflectional paradigms: nominal, verbal, and adjectival. The nominal paradigm is responsible for modifying nouns, such as in the use of pluralization or possessive forms. The verbal paradigm involves changes to verbs, including tense, aspect, mood, and agreement with the subject. Lastly, the adjectival paradigm modifies adjectives, as seen in the formation of comparative and superlative degrees. However, this research specifically concentrates on nominal and verbal infection to analyze them, and the emergence and accuracy criteria were used. The emergence criterion refers to a morpheme appearing in at least four distinct instances to satisfy this criterion (Pallotti, 2007). On the other hand, the accuracy criterion refers to 1973, Brown introduced the term Suppliance in Obligatory context (SOC), which establishes that a morpheme must reach 90 percent accuracy in context to be considered acquired. The data was gathered from the Mexican Learner Corpus (Flores & Moore, 2023), and it was analyzed using the software UAM Corpus Tool (ODonnell, 2008). This tool allowed the classification of learners errors through annotation layers based on the classification proposed by Akbas and Dincer (2021), Demarta (2012), Ardébol (2012), Mahmood, Mahmood, and Rasool (2020), and Fontana (2013). The tags used are target-like use, non-target-like use, which is divided into subcategories such as underuse, misuse (misselection, misrealisation), overuse, and unclassified. The results revealed that the inflectional morpheme with the highest frequency of use was the regular plural, with 320 tokens in total, of which 304 (96.825) tokens are target-like use. Lexical be is the second most frequent morpheme with 266 tokens, where 257 (96.62%) target-like use tokens. Then, the irregular past contains 130 tokens, with 106 (81.54%) reflecting target-like use. Meanwhile, regular past contains 80 obligatory context tokens where 65 (81.25%) reflect in target-like use, 15 (18.75%). Additionally, the third singular contains 55 tokens (78.57%) of target-like use. Auxiliary be has a total of 46 tokens, where 40 (86.96%) tokens show target-like, while progressive contains 42 tokens, where 36 (85.71%) tokens belong to target-like use. Finally, the morpheme with the least usage is the plural irregular with 21 tokens, in which 17 (80.95%) tokens reflect target-like use. In conclusion, the order of inflectional patterns observed in the oral production of EFL learners showed that the sequence typically begins with the learning of the lexical be, followed by regular plurals and the progressive form. Afterward, learners tend to use the auxiliary be, then move on to regular past tense forms, followed by irregular past tense forms. The learning process continues with the third-person singular inflection, and finally, learners master irregular plural forms. Finally, the relevance of this study lies in its contribution to the field as a result of the lack of corpus-based research that explores the specific linguistic errors made by Mexican speakers studying for a degree in English Language Teaching. By identifying and describing nominal and verbal inflection in learners oral production, this research provides valuable evidence about the learning process of EFL through the application of emergence and accuracy criteria.