Introducción English language gives great advantages to speakers of any language that is why this is studied worldwide. One of the most important elements when studying English is its morphological structures which contribute to the communicative competence. Morphological features of words such as affix frequency may provide semantic cues that can help in the learning of new words. Therein, regular inflection applies by grammatical rules, such as addition of -ed to the word stems for English past tense. Irregular inflection, in contrast, is less predictable and comprises various alternations of the word form (e.g., sleep – slept). Understanding of affix knowledge development is of great importance for both researchers and practitioners, since it might shed light on the process of vocabulary acquisition and the role of affix knowledge in reading. Competence is what speakers do with the language so that communicative competence is the know-how of the language. It may be affected by the situational context. The common European Framework for references for languages (CEFR) includes 3 levels of language competences; basic user, independent users and competent users. Communicative approaches toward language learning and teaching suggest that the purpose of language subject is to develop learners’ communication and interaction ability. To sum up morphological structures which can be regular or irregular truly benefit the development of the speakers´ communicative competence. Objetivos The aim of the research was to determine the influence of affixation in the communicative competence of the students from the English Program at Technical University of Ambato. The specific objectives were focused on the identification of the prefixes and suffixes that denote opposition, pluralization, meaning and grammatical categories. Another specific objective has to do with the recognition of communicative competence elements such as linguistic and translinguistic. Método This was quantitative research due to all the items were transferred into numerical data to get percentages and tendencies. Bars and charts were used to show the data obtained from the survey. Additionally, the research had a descriptive focus with the application of a validated survey (Alpha de Cronbach 0.801) that included a pilot administration of the survey. The survey consisted of 21 closed questions applied to 100 students from the English Program at Technical University of Ambato. Principales resultados The results portrayed that 59% of students state that teachers always used morphological structures constructed by <-ed> to change the verb tenses into past in words like work and worked. On the other hand, 73% of students maintain that teachers never the verb suffix such as <-en> in words like shorten as well as the suffixes that form plurals based on other languages structures such as cactus and cacti. In the same path, 61% of students state that teacher never use prefixes for word meaning as <mono-> in words like monolingual and prefixes that express the opposite as <im-> in words like impolitic. Additionally, 49% of pupils think that teachers frequently use prefixes to form nouns such as <-ment> in words like achievement. 52% of students admit that teachers rarely use suffixes to make to change word into adverbs for instance <-ly>, <-wise>, <-ward> in words as rapidly, likewise or toward. Conclusiones The morphological structures rarely used by teachers and students are the ones that denote opposition, prefixes that give meaning to words and formation of plural in reference to other languages. Additionally, the morphological structures with more difficulty are the derivational morphemes such as formation of plurals that are originated from other languages as cactus and cacti, suffixes that express opposition as impolitic, dissimilar; suffixes that imply meaning as monolingual or biotechnology, verb suffixes like shorten, and adverb suffixes like rapidly. Very important to mention that morphological structures promote the development of linguistic and translinguistic elements of any language since they are connected to the increasing of vocabulary which is the building block of a language. The study of morphological structures must be part of teachers’ knowledge so learning takes place during lessons.