Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could speak. talk you could speak. talk she could speak. talk we could speak. talk you could speak. talk they could speak. talk
V-ing form
I could be speak. talking you could be speak. talking she could be speak. talking we could be speak. talking you could be speak. talking they could be speak. talking
Perfect
I could have speak. talked you could have speak. talked she could have speak. talked we could have speak. talked you could have speak. talked they could have speak. talked
V-ing perfect
I could have been speak. talking you could have been speak. talking she could have been speak. talking we could have been speak. talking you could have been speak. talking they could have been speak. talking
Negation
Simple form
I couldn't speak. talk you couldn't speak. talk she couldn't speak. talk we couldn't speak. talk you couldn't speak. talk they couldn't speak. talk
V-ing form
I couldn't be speak. talking you couldn't be speak. talking she couldn't be speak. talking we couldn't be speak. talking you couldn't be speak. talking they couldn't be speak. talking
Perfect
I couldn't have speak. talked you couldn't have speak. talked she couldn't have speak. talked we couldn't have speak. talked you couldn't have speak. talked they couldn't have speak. talked
V-ing perfect
I couldn't have been speak. talking you couldn't have been speak. talking she couldn't have been speak. talking we couldn't have been speak. talking you couldn't have been speak. talking they couldn't have been speak. talking
Interrogative form
Simple form
could I speak. talk? could you speak. talk? could she speak. talk? could we speak. talk? could you speak. talk? could they speak. talk?
V-ing form
could I be speak. talking? could you be speak. talking? could she be speak. talking? could we be speak. talking? could you be speak. talking? could they be speak. talking?
Perfect
could I have speak. talked? could you have speak. talked? could she have speak. talked? could we have speak. talked? could you have speak. talked? could they have speak. talked?
V-ing perfect
could I have been speak. talking? could you have been speak. talking? could she have been speak. talking? could we have been speak. talking? could you have been speak. talking? could they have been speak. talking?
Interro-negative form
Simple form
couldn't I speak. talk? couldn't you speak. talk? couldn't she speak. talk? couldn't we speak. talk? couldn't you speak. talk? couldn't they speak. talk?
V-ing form
couldn't I be speak. talking? couldn't you be speak. talking? couldn't she be speak. talking? couldn't we be speak. talking? couldn't you be speak. talking? couldn't they be speak. talking?
Perfect
couldn't I have speak. talked? couldn't you have speak. talked? couldn't she have speak. talked? couldn't we have speak. talked? couldn't you have speak. talked? couldn't they have speak. talked?
V-ing perfect
couldn't I have been speak. talking? couldn't you have been speak. talking? couldn't she have been speak. talking? couldn't we have been speak. talking? couldn't you have been speak. talking? couldn't they have been speak. talking?