NO NO NO it's NOT your fault.
Please, don't guilt yourself.
*Oh, per Riley's posting- my son IS bi-lingual. Fluently in both languages.
My son, who is now almost 3 years old.... "had" a speech delay. Yep. But he is now no longer speech delayed! From about 19 months old, he had a Speech Therapist, which was FREE from our Regional local Zero-To-Three program.
Ask your Pediatrician about it. Every State seems to have one of these programs. But it is only "free" until 3 years old.
My son did not have Dysphagia or Apraxia or any developmental problems/issues. He was just slower to talk. MANY BOYS ARE. Per our Speech Therapist, it is often a "gender" difference, and 80% of her clients were boys!
Don't worry. A Therapist can really help assist your son and you.
Some Moms would even tell me "How come your son doesn't talk yet..." and they would talk to him like he was "stupid." (the nerve!). But, my son was also assessed as being 'advanced" in several developmental areas. And he has many gifts and abilities... and now he is so chatty we really know what he was thinking all this time!
Each child, has their "gifts" and even a speech delay is not a detriment. Don't worry. Focus on the positive... and certainly do NOT let anyone stigmatize you OR your son. Focus on the "gifts" your son has. Kids, can "feel" any negativity or stigmas against them... so just nurture your son, and take advantage of any speech therapy if possible.
*Einstein, didn't talk until he was 3 years old. Mozart, the musical genius, also had a "speech delay" as we would call it. Many gifted & talented adults, had speech delays or sensory issues. And, look at what they became! Today, they are called geniuses and unusual talents, that have benefited humanity and the arts.
It is not something that a parent is at fault for. It is just developmental and nature. But, speech therapy is very beneficial. My Son LOVED his sessions and his Speech Therapist.
All the best,
Susan