This is a love song built on a spelling joke, and it works. Gera Demara starts with the alphabet: of all the letters, his favourites are the ones in her name, and the one he hates is Ñ, the letter Spanish has and English doesn't.
Why? Because without it, so many of his problems would vanish. Look at the words he can't escape: soñar (to dream), niño (child), cumpleaños (birthday), señales (signs), años (years), dueña (owner), daño (hurt) and extraño (I miss you). Every one of them needs an Ñ. Take the letter away and he wouldn't dream of her, wouldn't be blowing out birthday candles wishing she'd come back, wouldn't miss her. His punchline is "Mi peor maldición es hablar español" (my worst curse is speaking Spanish).
It is a clever way to say he can't stop thinking about her: the language itself keeps reminding him. For a learner it doubles as a neat list of everyday Ñ words, plus some useful conditionals like acabarían (they would end) and no hubiera (there wouldn't be).