twitter

All in a twitter; in a fright. Twittering is also the note of some small birds, such as the robin, &c.

Twitter
·vt To utter with a twitter. II. Twitter ·noun A slight trembling or agitation of the nerves. III....

Webster's Dictionary of the English Language
twitter
to tremble ; a Teut. TITTERN, tremere, both from the sound produced. This is a word of general use. ...

A glossary of provincial and local words used in England by Francis Grose