The iPhone automatically updates its dictionary based on your usage. When I first got my iPhone, it kept correcting me everytime I typed my friends' names. After several times, it doesn't correct me anymore. Just a few days ago, when I typed a word that I use commonly, I noticed that it didn't correct me anymore. It learns. But I agree with the original poster that there are some words, such as "texting" that it won't add to its dictionary no matter how many hundreds of times we type it. The dictionary auto-update "learning" does not treat all words equally. Apple, please fix this.