Minions speak a fictional language called "Minionese," sometimes also referred to as the "banana language." It is not a real language but rather a playful blend of words and sounds taken from several existing languages, including English, French, Spanish, Hindi, Korean, Italian, Filipino, Indonesian, and others. This mix gives Minionese a unique and amusing sound that conveys emotions and ideas through a blend of recognizable words and gibberish. Some recognizable words and phrases in Minionese include:

• "Bello!" meaning "Hello!" (Italian)
• "Banana!" meaning "Banana!" (English)
• "Poopaye!" meaning "Goodbye!" (similar to French "Au revoir")
• "Tank yu!" meaning "Thank you!" (English)
• Counting "1, 2, 3" as "Hana, Dul, Sae" (Korean)
• Food-related words like "gelato" (Italian for ice cream) and "poulet tikka masala" (French and Indian cuisine)

The creators designed Minionese to sound playful and universal, making the Minions' communication fun for audiences worldwide, despite it being mostly nonsensical gibberish mixed with real words from various languages. The character Gru, in the Despicable Me movies, understands Minionese, supporting the idea that in the movies' universe, it functions as a real language to some extent. In summary, Minions speak Minionese, a fun, constructed language that mixes multiple real-world languages to create their unique speech style. It is characterized by a combination of baby-talk sounds, food words, and phrases borrowed from many languages across the globe.