How is language evolving on the Internet? In this series on internet linguistics, Gretchen McCulloch breaks down the latest innovations in online communication.

Using "u" as an abbreviation for "you" is well-established in casual written English, especially online. But in the age of autocomplete and touch typing, is "u" really just used to save space and time, or are there more subtle things going on?

A post on tumblr asks the same question:

pls explain why ‘you’ sometimes needs to be ‘u’ and ‘u’ needs to be ‘you’ and how come i will mix and match my u’s and you’s within the same post or even the same sentence

First, let's check if this is a widespread phenomenon. It is, and not just on tumblr. There are lots of tweets that contain both "you" and "u." I'm going to put them into groups to make them easier to talk about, but let's note that "u" isn't just to save space—the majority of these tweets are already much shorter than 140 characters.

The most obvious thing to notice is that "u" is far more likely to occur with "I love u" than "you" is.

Tallahassee I really enjoyed performing for you guys tonight. I needed that stage therapy today! I love u guys 
(@kmichelle)

" Perks of being followed by OCHS Confessions: You can tell them anything and they message you every week wishing you a great week. I love u 
(@ConfessionOCHS)

normani if this tweet reach 1k rt you follow me? is my dream to have your follow.I love u so much my beyonce @NormaniKordei 
(@stylesexuada)

@jarpad today is not a good day for me can you please give me a virtual hug? i love u endless @suchaknitwit 
(@loxluminous)

Remember, anyone can love u when the sun is shining. It's in the storms where u learn who truly cares for you
RT @terri_dwyer

(@paul_steele)

"U" is also found with the heart emoticon and emoji, unlike "you".

(@Mamasp00n)

(@JessieJDecker)

The tweets above and below look like an exception ("Love you so much" and "You little fluffball have been very well-loved"), but notice that in the first tweet, "u" comes after the heart emoji, while in the second, well-loved is a more formal expression than the plain "I love u"s we've been seeing so far.

What's left, when we take out the love-related tweets? Well, it's a bit of a mixed bag.

When you're at a party with ppl u don't know and your friend disappears
(@CuteAnimalsBaby)

Saying you are better than most of the people in the team u want to join won't actually help u in the team !!
(@CISKATZ)

Idk how to flirt Ima just stare at you until u marry me
(@placelikethis)

I'll do shoutouts tomorrow also, so if u didn't get picked tonight you just might tomorrow
(@sammyswilk)

Many of my followers are current or former military. Thank you for your service. It's appreciated. We may need u to HELP RECAPTURE AMERICA!
(@BlacknRight)

Find me where this is and I'll give u anything you want!
(@EatSleepGrier)

Thank you for being so wonderful! Hope every last one of u sleep amazing or have a great day wherever you are <3
(@CreatureHub)

If u have curly hair you understand the struggle
(@funnyjoke)

how you gonna get w dimes if u keep objectifying women
(@trevso_electric)

IN MY WORLD ZAYN IS STILL IN ONE DIRECTION SO SAY WHAT YOU WANT BUT STAY OUT OF MY WORLD THANK U
(@hucklelouis)

when u meet your girlfriend/boyfriend's parents for the first time & you want to make a good impression
(@TumblrDaiIy)

It's not totally conclusive, but overall, the parts of the tweets with "u" do seem a bit more emotive than the parts with "you". For example, compare "ppl u don't know," "help u in," "until u marry," "need u to HELP" with the you-parts of the same tweets: "When you're at a party," "Saying you are better," "stare at you until," "Thank you for your service."

But I don't even know what to say about "u" versus "you" in this one:

If she's comfortable around u she'll tackle you, sing to u, be weird around u, dance for you, scream at you, take ur food & be mean to you.
(@DrakeNYC)

What might be going on here? Well, English pronouns haven't always looked like this. We used to have thou/thee as singular, while you/ye was only used to address multiple people. Later, as happened in many European languages, things got a little more complicated. We started using "you" to address high-ranking individuals (compare with the royal "we"), and gradually this respect trickled down until "thou" was pretty much lost to normal speech by 1600.

But although our current state of thou-less-ness may seem simple to anyone learning the niceties of French tu/vous or Spanish tu/usted/ustedes, it actually created two problems. First, we were no longer able to make it clear that we were addressing more than one person—hence the rise of y'all and you guys. And second, we lost the ability to be subtly intimate or insulting with someone, which might be what's going on with u versus you: "u mad?" could come from a troll or a close friend, but it's clearly more personal than the neutral "you mad?"

Have we fully regained a formal/informal distinction? Of course not. For one thing, it would be stretching the evidence to say that the tweets above show a consistent formality difference between "u" and "you". For another, there are still many, many people who just consistently use one or the other—trust me, I've looked through a lot of their tweets recently. And I'm not even going to try to get into the complexities of "ya" and "y'" (as in "y'know") in casual writing.

But if we do end up regaining a full-fledged formality distinction in second person pronouns, could we look back at this and see the beginnings of it? I think it's quite possible, u know?