...vestía la ropa con la que tú sólo puedes soñar
"...she wore clothes that you can only dream about"
[Caption 10, La Mala Rodríguez > La niña]
In caption 10 of María's song La Niña we are told that the protagonist wore clothes con la que tú sólo puedes soñar, "that you can only dream about." Soñar is the infinitive "to dream" and of course is related to the word for dreams themselves, sueños. The tilde (~) over the n tells us that this n is pronounced with the "palatal nasal sound" or [ny], like what we hear when we say the English word "canyon" (which is, appropriately, cañón in Spanish). Soñar, therefore, is pronounced [sonyar].
Being a rapper and therefore a poet, it's no surprise that a few lines later she ends another line with a very similar looking infinitive.
...tu teléfono no deja de sonar
"...your phone doesn't stop ringing"
[Caption 13, La Mala Rodríguez > La niña]
By dropping the ~ over the n in soñar we get sonar, which means "to sound" and also, as in this case means "to ring." Because there is no tilde over the n, the word is pronounced with the standard [n] sound we are used to in English. As so often happens, in this case the infinitive sonar is best translated into English using the present participle ("ing") form of the verb, which gives us "ringing."