加わる

1. Origins, structure, and basic meaning

• Structure: 加わる(くわわる) is an intransitive verb for a person or element joining an existing group or becoming an addition to something.
• Basic usage: It covers both an interpreter joining a team and acidity being added to a sauce.

2. Common pitfalls and similar expressions

• The subject's role versus 加える
  • 酸味が加わる describes acidity being added. 酸味を加える describes someone adding it, using the transitive verb 加える(くわえる).
• に marks the group joined
  • In チームに加わる, に marks the group being joined. が can mark the person joining.