...being able to speak (and write) properly is reflective of who you are. You may be the most capable, experienced, and qualified operator in the world. But if you don't communicate well, people will see you as, at best ignorant, at worst stupid.
The more proficiency you have with effectively communicating technical issues, the farther you will go in your career. Any career, but more important to a technical career. If you compile a 100 page technical report (which many young nukes in commercial or the Navy do NOT do...yet), and it's full of spelling errors, your technical content and all related conclusions are brought into question. When you give your boss something to sign, do NOT ever assume he'll find your mistakes or treat it like a "first draft". "Complete Staff Work"...this could be a long and detailed separate thread alone.
In contrast, I've read reports with perfect grammar and spelling that have worthless technical content. The secret (shh...don't tell anyone) is to have BOTH good, sound technical conclusions AND perfect grammar/spelling. Then, be prepared to publicly present your conclusions before a large audience. If you can do all that, you'll be well on your way to senior officer/manager level. If you're still in Boot Camp though...don't lose too much sleep over these skills. Simply concentrate on the "rules of a military sentry" for now and just do what you're told. Good mentors in the future will steer you where you need to go. Meanwhile, spare us the SMS text etiquette...that level of informal communication doesn't fit into a nuclear community forum.
Very few people have the same "attention to spelling/grammar detail" in cell phone SMS messages, chat room messages, Facebook updates, personal emails, work emails, personal letters, formal letters, Navy FitReps, or Congressional letters. Browsing business articles speak of the evils of informal emails being released beyond their intended recipients. (Authors beware!) So, what can you conclude about someone's spelling/grammer on NukeWorker.com? Well, if they're posting like they do in a chat room or SMS message, then they're not taking our community very seriously (and they get a well-deserved commensurate response).
I don't conclude they're "stupid", but maybe a bit lazy and definitely overly informal. While there are no rules here on grammar, the experienced/senior forum members can simply choose to ignore the ignorant. Personally, I'm content to see two seemingly junior boot camp "NUBs" publicly counseling each other with bad advice in the forum without recognizing the lack of senior member feedback to their issue. Some people just need to learn the hard way. I've learned in 20+ years that if someone senior to you ignores your question/statement, it probably was NOT an accident.