We who supervise Portuguese instruction at the Foreign Service Institute have observed that the majority of students who already speak Spanish make better progress in Portuguese than those who do not. Although the Spanish they know so well makes frequent and unwanted intrusions on their Portuguese, it also gives them considerable insight into the new language. So much of what was learned in Spanish is now applicable to Portuguese. Our conclusion is that the advantages of this transfer factor far outweigh the disadvantages of interference.
This manual has grown out of a need to supply students with a guide to making the Spanish to Portuguese conversion. It is written in a casual, informal style, not unlike the conversational style of the classroom, where much of its content had its origin and initial expression. It provides an extensive examination of those Spanish / Portuguese correspondences that have proven most troublesome to students, correspondences which you must be particularly aware of if you wish to keep your Portuguese separate from your Spanish. This manual is not exhaustive in its approach, it does not attempt to cover alI the differences between the two languages. An attempt to examine the distinctions between European and Brazilian Portuguese is beyond the scope of this manual. On the assumption that the majority of users will be studying Standard Brazilian Portuguese, I have elected to write about this variety.
We recommend that you read about the sounds and do the pronunciation exercises at the very beginning of your Portuguese course, for it is then that you will experience most of your interference from Spanish pronunciation.
Resource: Foreign Service Institute