conversational ability; speaking ability
Refers to one's skill in carrying on a conversation, often in a foreign language or social context.
He has high conversational ability in English.
To improve your speaking ability, practicing actual conversation is best.
語学力 is broader, covering overall language proficiency including reading and writing, whereas 会話力 focuses on spoken interaction.
Compound of 会話 (kaiwa, 'conversation') and 力 (ryoku, 'power, ability').