I'm not familiar with many other languages, but one I have some contact is Tagalog. It has three words, one for each meaning of the first person plural.
- Tayo: "we, all of us", including the person addressed. When we (tayo) are going to the movies, you are cordially included in the invitation. It is so intrinsic to how people relate that this word is often implied and not said: "Ka-in na!" Means "Eating now" but it really means, when a younger person says it, "I'm eating now, but I'm not comfortable eating because you haven't joined me." and the older person waves a blessing for the younger person to continue. When an older person says it, it means "You will eat now." allowing and requiring the younger to sit at table.
- Kamé: "only us", excluding the person addressed. Usually stated among equals or from older to younger "We (kamé) need to discuss your grades" means the child must steer clear of her parent's bedroom, and perhaps reread and take notes on the Noli Me Tangere before the test this week.
- Kita: "You and I". This word actually refers to a single entity and is used in special modes of address. It refers to the (single) person that exists from the unity of the speaker and the addressed. "Mahal kita" is the most often use of the word and a loose translation is "I love you." But its deeper meaning is "This single entity that is you and I together exists bound in love." Kita has no separation between the speaker and the one spoken to, because they are one. When he says "Mahal kita," and she roles her eyes and sighs, it is the unity of one single action. There is no love being sent out by one and then received by the other. The love simply subsists in the unity of the two.
Is not kita a description of the Triune God? Father and Son, I and Thou, and the Holy Spirit, Love Divine, connecting the Three-in-One? Reflecting on the annual homily of the Trinity, I find it now humorous, and obvious, that it's so difficult to explain this mystery to English speakers (and sad correlation: how few English-speakers get the Trinity), but the Philippines has a near 100% Catholic population: they don't need to get it, they have the concept imprinted on their minds, and consequently hearts and souls, from the day they commence speaking.