We live in Spain, and me and my wife have decided our 9 months baby to be tri-lingual: She speaks with him in Spanish outside of home, I speak with him in Catalan outside of home, and we both speak with him in English when we are at home.  Note that we live in a region of Spain where Catalan is not official language, therefore it is not spoken or taught in schools.

I am engaged in developing his reading skills at this stage,  but I am not sure if my approach is correct and I would like to know your opinion.  Do you think that it will be beneficial for his school experience if I teach him to read in English? Note English is not taught as a foreign language in the schools until children are 9 years old. I could teach him to read in Catalan, which phonetics are similar to Spanish (except some additional vowels), but I've chosen English for practical reasons (teaching material availability, future opportunities, etc.).

Although Spanish will be the main language in the immediate environment and the school of our baby, I think that it is not an option for me to teach him to read in Spanish (I do not use this language to speak with him). My wife is supportive, but not involved in stimulating our baby in this way.

Should I teach to read English (more future opportunities, more teaching material), Spanish ( school and main environment language) or Catalan (my main language to speak with him)?

Thanks for your opinion and sorry for the long post.