The English language has more than its share of homophones — words that sound alike, but have different spellings and meanings. It's not a problem in oral language, but using the wrong word in written communication can be annoying, if not misleading. One set of homophones that is often misused is there, their, and they're. Let's review.
They're is a contraction, the joining of two words into one. In this case: they and are. Instead of saying (or writing),"They are going to buy this house," we combine two words into one and indicate the missing letters with an apostrophe. Thus they are becomes they're.
Their is a plural possessive pronoun that functions as an adjective. Sounds technical, but it just means that something belongs to someone – in this case multiple someones, and it modifies a noun. "Their children are so well-behaved they must take after our side of the family," Gramma quipped. The children in question belong to the mother and father. Their not only identifies the relationship, but specifies which children. The children that belong to that particular set of parents. The important thing to remember if you're not sure whether to use their or there is to ask yourself, does this belong to someone? If not, the proper term is probably there.
Used as an adverb, there has multiple meaings and uses, which may explain why it's frequently misused. It can mean a place or location. Put the dishes over there – as opposed to here. "There," he pointed, "is where the attack occurred."
There also refers to a stage or stopping point. He paused there (at that point) to reflect on what had just happened. You can also use there to note in relation to or in a particular matter. "I disagree with you there," the philosopher argued. And there is used to call attention to something or someone. "There she is, Miss America. " (Though that familiar song will no longer be part of the pageant.)
There can be used as a pronoun when it introduces a sentence or a clause in which the verb comes before the subject or has no complement, though beginning a sentence with there is generally considered weak writing. There are times it works. When you make a conscious decision to do so for emphasis. If, however, you're beginning many sentences in that manner, look for stronger nouns to make your point. Often, there is a throw away or unnecessary word, confirming that there really is no there, there.