This is a mouse.
This is a computer mouse. They kind of look similar, hence the name of the computer mouse.
Here are two of the little critters. More than one mouse, they are mice. Three mice, and the collective noun is plague.
But what have we here? Mice or mouses? I prefer mouses in this case.
I try to explain English to people who don't have English as their first language, but at times it is impossible. Things are just how they are with no reason.
Certain letter combinations are difficult for some non English speakers. Long has the English speaking world mocked Germans for their inability to pronounce th. Asian speakers struggle with it too. I was talking to a Cambodian friend about words and he asked me a question about werbs. You mean verbs, I replied. Yes, werbs, he said back. Had he misread the word, even though he knew exactly what the word meant, or maybe Cambodians can't pronounce the letter v.
Language is endlessly fascinating to me.