The rain in Spain stays mainly in the plain is an English saying which is often translated as La lluvia en Sevilla es pura maravilla- don´t ask me where these sayings come from! they sound weird both in the English and in the Spanish version. The funny thing about this saying is that it usually represents the difficulty of the pronunciation of the English language.This old film, My Fair Lady, shows how hard it is for an uneducated British woman to speak perfect English; her teacher mentions the musical mixtures of sounds, the majesty and the grandeur of the English language... we don´t have to think that high but we should follow her example: try again, and again, and again... until we accomplish it.
This video is a little bit long but only the first part is focused on the pronunciation
You don´t need subtitles, do you? Well, just in case, you can read the translation in the subtitled version below