A committee disagrees with the proposal.
A committee disagree among themselves.
Morphology
Morphology is concerned with word formation, both inflectional and derivational.
Inflectional morphology is about how nouns are pluralised (house, houses; mouse; mice) and verbs are conjugated (be, am, are, is, was, were, being).
Derivational morphology is about how new words are formed from existing words, for example by adding an affix (success + ful → successful; un + successful → unsuccessful).