be fickle, not to stick to one's words

under tongue, stay with words what you said

back out of one's word

to be a fluent and sharp speaker

to cut one's tongue off

to be left dry-tongued, to speak a lot, loquaciousness

to pronounce correctly

to speak truthfully

to be unable to speak, become helplessly speechless

be rude, be foul-mouthed

speak haltingly or with bated breath, speak softly, mince one's words

be learnt by heart, constantly recited or uttered

be tongue-tied

to have a bad pronunciation

to be in unison

to differ from one's word or command

reference to talkativeness

to be eloquent and smooth-spoken

be impudent, be insolent

to speak bluntly, discourteousness