"To speak a word" means to say something, to communicate or express oneself verbally.
Sentences with «to speak a word»
Are you a pharmacist or pharmacy technician who has Spanish - speaking patients but can't speak a word of Spanish and don't have time to learn? (pharmacist.com)
Though he has never spoken a word in his life, at age 5 he found a way to say anything he needed to. (religion.blogs.cnn.com)
Either I had to attend school (not likely, since I couldn't speak a word of German) or come up with some sort of worthy project to keep me busy. (victoriastrauss.com)