In Alkaseem, Saudi Arabia, we were surrounded by Arabic-speaking people. I mean there were people from other countries too. Like from Sudan, Egypt etc who all speak in Arabic. I don't know how my parents learned to speak Arabic very well. Mom said, first she uses to copy whatever she heard.... then gradually she became an expert in it. I never learnt (Accept my mother language) any language like that.
We, the kids didn't meet with other people much. So we didn't need to speak a different language. When needed my mom was there to translate. So, I never felt to learn Arabic. After living for 2 years in Saudi Arabia I learnt a couple of words only.
One day, mom asked both sisters to go to a grocery shop, which was very near to our house. She said asked the shopkeeper to give tomatoes. He will understand your language. Well, we doubt. But my mom was an iron lady, we had to go and ask. As expected, he didn't have a clue what we were asking about. He showed rice and other things to point to it. We tried a couple of times then returned home. My mom was so disappointed with the two girls. She went to the shop and asked in Arabic. The man laughed out loud and said, "Oh, Tomath?" Then he gave us tomatoes. I was thinking why he couldn't guess tomato and tomath could be the same thing...
After reaching Canada, I have faced the same thing a couple of times. Just for a little difference in accent, people couldn't understand a thing. One day a Chinese guy asked me something. I could understand that he is asking something in Bangla, after listening 4/5 times. He was very fast and his accent was Chinese. Now I understand, why others couldn't understand my language because of my accent.