Questions & Answers about Здесь наши соседи, а там их матери.
Wait, why is the plural of мать (mother) матери? Where did the "-ер-" come from?
Мать is a highly irregular noun in Russian. Whenever it changes form, like when it becomes plural, a hidden -ер- appears before the ending. So, "mothers" is матери. You will see the exact same thing happen with дочь (daughter), which becomes дочери in the plural.
The singular word for "neighbor" is сосед. Since it ends in a hard consonant, shouldn't its plural be соседы?
You would normally expect a hard consonant to take the -ы ending. However, сосед is an exception. In the plural, its final consonant becomes "soft", so it takes the soft ending -и to become соседи.
Why does "our" (наши) have a special plural ending, but "their" (их) doesn't?
Words like "my", "your", and "our" change their endings to match the gender and number of the noun they belong to. Because соседи is plural, наш changes to наши. But the words for "his" (его), "her" (её), and "their" (их) are completely frozen. They never change form, no matter what noun comes after them.
The English translation says "...and there are...", so why does the Russian sentence use а instead of и for "and"?