I live in Mexico. Previously I taught English in China for several years and it was necessary to learn their language to adjust my teaching style to their needs. Now, living in Mexico I can see very clearly some of the problems facing Latino students who desire to learn English.
I just finished converting my Chinese phonetics program to Spanish to aid hispanohablantes. There are less sounds in Spanish than the target language English, therefore native Spanish Speakers need to be taught these sounds which, from their point of view, are unknown to them...not within their experience.
The URL is here. http://www.elaanslist.com/display/fluency.php . It is not an app, but instead it is a screen cast used for self-learning. It requires personal dedication and verbal discipline to complete. It is to be used with your current English lessons.