1. One that speaks, in what ever manner.
2. One that proclaims or celebrates. -No other speaker of my living actions.
3. One that utters or pronounces a discourse; usually, one that utters a speech in public. We say, a man is a good speaker or a bad speaker
4. The person who presides in a deliberative assembly, preserving order and regulating the debates; as the speaker of the house of commons; the speaker of a house or representatives.