The following work tries to analyze the possible fossilization errors of the students when acquiring a second foreign language. For this purpose, two languages have been chosen: maternal (Spanish) and foreign (English). In the present work we have examined the effects of the Spanish language and the English language when learning another language as a second language (EFL) and a difference has been found both in the phonetic, the lexicon and in the grammar between the two languages. The order of words between Spanish and English is also different. When learning a language the apprentices almost always make some mistakes that in the long run could be fossilizable or quickly become fossilized. The fossilization in the lexical plane occurs when we change the words that are similar to the native language (L1) because the teachers think that these words mean and pronounce themselves in the same way in (L2). There are some unique words and phrases in L2 that are similar in L1 since they come from the same origin. Even so, there are words that can change from one place to another, changing the meaning and pronunciation. Phonological is another aspect that we must take into account listening comprehension as a way to focus on the pronunciation of reading, analyze the structure of writing and the fluency of speech.