No, the vocabulary of a corpus does not remain the same before and after text normalization.
Reasons are:
● In normalization the text is normalized through various steps and is lowered to minimum vocabulary since the machine does not require grammatically correct statements but the essence of it.
● In normalization Stop words, Special Characters and Numbers are removed.
● In stemming the affixes of words are removed and the words are converted to their base form.
So, after normalization, we get the reduced vocabulary.