What if my partner doesn't know their own love language?

Watch what they complain about. "You never spend time with me" = quality time. "You don't appreciate what I do" = acts of service. "You never say nice things" = words. "You're not affectionate" = physical touch. "I feel forgotten" = gifts. Their complaints reveal their unmet love language need.

How do I test if I've identified the right language?

Deliberately express love in their suspected language and observe the response. Try consistent quality time for a week; if they seem happier and more connected, quality time is primary. Try specific compliments next; if the shift is less dramatic, it's secondary. Testing takes weeks but reveals truth.

What if my partner has multiple equal love languages?

Some people have two strong languages. Instead of debating which is primary, diversify. Give acts of service, quality time, and affirmations. You'll cover their needs and prevent the resentment that comes from always expressing the same language.