noun
Refers to a person who speaks, especially in a formal setting such as a meeting, debate, or conference. Not typically used for a casual conversationalist.
会議では、発言者は手を挙げてから話してください。
In the meeting, speakers should raise their hand before speaking.
次の発言者は山田さんです。
The next speaker is Mr. Yamada.
スピーカー is a common loanword for a speaker at an event, but can also mean a loudspeaker. 発言者 is more formal and unambiguous.
Compound of 発言 (hatsugen, 'utterance, statement') + 者 (sha, 'person'). The reading is straightforward on'yomi.