I often hear friends of my generation complain about the speech of young people. It seems to be the privilege of being 50+ to play the grammar police, always on alert for signs of slipping standards.

It might surprise them, then, to learn that Millennials themselves have strong feelings about proper language use. You wouldn’t think the generation that invented textspeak and emoji would be so passionate about the subject. Yet according to a Harris poll conducted in partnership with Dictionary.com, 74% of young adults object to grammar and spelling errors, especially on social media.

Because they care so passionately, and because I care about my millennial friends, here is a list of 10 common grammar and punctuation mistakes that pop up frequently in their communication.

1. Abusing the apostrophe. They belong in possessives and contractions, not plurals. Period. So “Sunday’s a good day” is fine. “Sunday’s are the best time to go” is not.

2. There’s no their there. Speaking of possessives… they’re is the contraction for they are. Their spelling is incorrect when they use it as a possessive.

3. It’s tricky to nail its. In the same vein, i-t-s is a tricky one. As with they’re, it’s is the contraction–short for it is. Its is possessive. Think of it this way: you wouldn’t say hi’s, her’s, or their’s. It’s really quite simple.

4. They could not care less that they could care less. Ask Weird Al about this one. If you really don’t care, and you want it to show, make sure the not is there.

5. You and I–not always right for me.You and I just sounds more appropriate and formal, doesn’t it? But it not always correct. Simple rule of thumb: If you would use “me” for the singular (That cake belongs to me/I can eat that cake), then use it for the plural (That cake belongs to you and me/You and I can eat that cake.)

6. Commas should be used like salt–sparingly. Most people struggle with this, myself included. Many writers insert a comma whenever they pause think, whether or not the sentence really needs it. If you find yourself tempted to do this, write the whole sentence without a single comma, then go back and add one where needed.

7. Literally inaccurate use of literally. It has become a popular term for adding emphasis: I literally couldn’t speak. You should only use it, however, if you are stating a fact…for example, if someone was pinching your tongue with barbecue tongs. There is literally no place for the word in hyperbole.

8. Defiantly misspelling definitely. Very few people actually confuse the two terms. Despite that fact, it remains a common typo, especially in texting and e-mail. Take a moment to proofread before you send. If you see it, don’t be defiant. You should definitely fix it.

9. Allotting word status to alot. Even if autocorrect allows it, and people do it a lot, alot is not a word.

10. Letting your Capitalization get Out of Control. In a regular sentence, only proper nouns (the given names of specific people, places, or ideas) need to begin with a capital letter. Even though it is a seductive way to add emphasis, try to avoid the T temptation.

The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.