14 months is not late - normal is 9-18month range. Boys speak later than girls. Bilingual is great for the brain - it does not delay speech or confuse them - it's really a bonus. Hearing test is smart. Other important things are to keep him away from the tv/movies - that really hurts their developing attention span and nobody ever learned a language by watching tv. Just love and talk to him; I get tired of talking, and find singing it good - they hear my voice and hear words but it less tiring on me! Listen to songs you like - as they'll get used to whatever you play!
Part of the reason he throws tantrums is that it works. It will take time and effort to break that pattern - but the sooner you do, the better for him and everyone else.
Teach him sign language. Again that does not slow development and takes away a lot of the frustration kids have when they are not talking. They understand so much (we all notice that in our kids). Sign language will give him tools to communicate peacefully - like "Elmo" - you make up a sign for that. "Baby Sign" worked for us. Just use the sign every time you say the word; it will take him a while (days or weeks) to learn. Once he uses the sign, give it to him immediately so he knows signs have meaning and get peaceful results.
Lastly, you can contact Early Intervention - ask your pediatrician - and they will come to test your son. Even if your ped. doesn't think your son needs it, just peacefully insist on the tel. no. It is free and even if the son qualifies for services, you are under no obligation to sign him up. (I have a daughter with Down Syndrome so that's how I know about these things). Early Intervention is the government program for birth - age 3 or 5 (depending on where you live) for services for child who have developmental delays whether they are just premies catching up for a bit or with something more long term, like my daughter.
I hope this helps.