Serious and frequent criticisms by students in the ESL (English as a Second Language) Program attempting to master the English language are the chaotic spelling of English words and the lexical and grammatical irregularities in English. In many cases, these exceptions originated during the Old English Period (450-1100). Thereby, they may seem illogical, senseless, and unreasonable at a simple glimpse to any ESL student. However, if they are analyzed within an historical context, each case becomes a rich, historical trait that makes English even more a particular and interesting language to acquire, understand, and master. The present study gauges how significant it is for ESL teachers to have knowledge not only of English but also of the peculiarities of the English language. This manuscript introduces the value and relevance for ESL teachers to have the knowledge of the historical background of the grammatical rules of the English language in order to explain to their ELL students how some exceptions have retained their original traits and how others have become simplified through analogy or leveling during the following centuries until Modern English.This study is significant to ESL teachers as it presents the results of a study carried out in Charlotte-Mecklenburg Schools to find out which irregularities cause the most struggles to ELL students and which struggles are particular to the nationality of ESL students. The outcome of the survey is a useful tool for ESL teachers to foster the academic weaknesses of the different ethnic groups and to teach the exceptions of the English language in a relevant and meaningful way.