The most common and standard placement of adverbs of frequency in a sentence with the verb "to be" is after the verb: "People are often..." "People are always..." "People are usually..." "People are never..." "People are sometimes..." Sometimes, they're placed at the beginning of the sentence, followed by a comma (like in this sentence). In some instances, they're placed before the verb "to be": When it's a short answer to a question: "Is it hot in Egypt?" "Yes, it often is." When you want to emphasize the adverb. For this, you invert the subject–verb order and place the adverb at the beginning: "Rarely am I late." Here, the sentence structure is "adverb + verb + subject". This puts the emphasis on the adverb. The sentence structure of "People often are talkative" is sometimes used in spoken/informal English, but it's not standard and not common. Usage statistics of "are often" vs. "often are": http://bit.ly/2CqJGj7 Usage statistics of "is often" vs. "often is": http://bit.ly/2CsTh8S

"People are often talkative when it comes to sports" sounds more correct to me. If there is no auxiliary verb, you put 'often' in front of the verb, unless the verb is 'be'. If the verb is 'be', you put 'often' after it. As to 'usually', it refers to experiences that are habitual or customary. The same condition applies to it, so you might want to say: 'People are usually talkative when it comes to sports'.

People are often talkative when it comes to sports. sounds better to me people will get your meaning with ether