This is a ranchera that tells a tiny, sad story in a few lines. The singer is walking past a palm grove and sees a beautiful girl with a "boquita de coral" (little coral mouth) and "ojitos dos estrellas" (little eyes, two stars). He asks who she is with, and she answers in tears: "Sola vivo en el palmar" (I live alone in the palm grove).
The rest of the song is her voice. "Soy huerfanita" (I'm a little orphan girl), she says, with no father, no mother and not even a friend to comfort her. Notice all the diminutives: boquita, ojitos, huerfanita, solita. Mexican songs love the -ito/-ita ending to make something sound tender, and here it makes her loneliness feel even smaller and sadder. The last image is the best one: "solita voy y vengo como las olas del mar" (all alone I come and go like the waves of the sea).