Mystically Inclined:
I have to agree with the OP here. I just joined the site and am starting my first game. Some of the players are trying to get us all into colored speech to represent languages. It's distracting to read, an added hassle to write, and leads to lazy grammar.
People have said that colored speech allows them to pick the speech out easier. In other words, it helps them to better skim the posts. My take on that is: if the people I'm playing with want me to go through extra effort to make it so they can spend less effort reading my posts (and missing all the non-verbal stuff I've written) then why am I gaming with this person?
I've only written a few in-character posts as of yet. So far I've been adding color just to get along with everyone... but yeah. It's unnecessary work, a bad grammar practice, and (if you think of it as setting your post up to be easier to skim) kind of insulting. :/
I have been on RPoL for eight to nine years. I use colored speech. In fact, I far prefer it. As I have stated earlier in this discussion, I even find it necessary due to ADHD and health problems. My grammar, punctuation, and spelling never suffer from my long-term use of the tool jase so wisely implemented in his wonderful site.
And as jtcbrown and srgrosse explained, it isn't for "skimming" over your posts during game-play. It can, however, help people with ADHD, dyslexia, Autism, and medical conditions involving the eyes or blood vessels of the eyes to break apart and separate large chunks of text. It can help them to organize what is being said versus what is being implied via actions, stated body language, and facial expressions. And, finally, as jtcbrown and sgrosse said, colored text is an extremely efficient tool when previous posts, often from years ago, need to be 'skimmed' to jog a DM's or PC's memory. For example, earlier today I needed to look back at a post written weeks ago to remember what room my character was supposed to go to. Because we used colored text, I was able to look for the appropriate color to find posts by the correct character and, thus, find the speech text very quickly. It saved time and frustration. My post, of course, still had proper grammar, punctuation, and spelling.