Strong form and weak form in English conversation

Generally, content words such as nouns and principal verbs are stressed, while structure words such as articles, helping verbs, etc. are not.

As a rule, structure will take the weak pronunciation which means that the vowel becomes muted.

For example:

But usually there is no change of spelling, only the pronunciation is different:

Tell him to go
strong forms /hɪm/ /tu:/
weak form: /tel əm tə gəʊ/

Students who are learning English usually use only strong forms, and they sound very unnatural.