Here is a list of five of the most common grammatical mistakes that are made by English speakers/writers. This list is merely a quick glance; these matters are dealt with in detail as well, in appropriate sections.
Subject Verb Agreement: Learners often get confused with using the appropriate form of the verb with the subject of the sentence. For example, ‘I live in India’ and ‘He lives in India’ is the correct subject verb agreement of the verb ‘to live’.
Possessive Nouns: Non-native speakers of the English are unsure about showing possession while writing or speaking in English. For example, ‘The book belonging to the girl’ can also be referred to as ‘The girl’s book’
See also: Possessive Nouns
Comparison of adjectives: We add ‘er’ to compare short adjectives like pretty and thick; and we add ‘more’ for longer adjectives like handsome and intelligent.
See also: Comparison of Adjectives
Punctuation mistakes: Punctuation errors, too, are very common, especially in the use of semicolons and commas.
See also: Punctuation Rules
Singular and Plural: Many new learners make mistakes in forming the plural form of singular nouns.
See also: How to make plurals