Stem+suffix=Another stem

[stmammadov]

Stemming happens to be incorrect sometimes when the stem of a word and a suffix together is the stem of another word.
Example: "qız"+"ın"="qızın".
Although the stem of the word "qızın" is qız" in some contexts, it is never identified correctly since the verb "qızın" exists as a stem in the dictionary.
Another example: "al"+"a"="ala".
A special case of this problem occurs when some suffixes behave as both derivational and inflectional. As the words list contains all derived forms of a word, such words are never stemmed though those suffixes may sometimes have inflectional role.
For example: "hissi" = "hiss" + "i"
In this example, "i" is an homonym suffix and this word is not stemmed in any of the following cases:
"Həyəcan hissi" - inflectional, should be stemmed;
"Hissi qavrayış" - derivational, already in stem form.
Another example: "ma" and "mə" suffixes are both derivational (creating noun) and negation suffixes. Therefore, negated verbs which are also nouns are not stemmed.