I'm complete obsessed with the letter /f/ these days. I've been working around the clock and nonstop with Christian on the /f/ sound, and I am Fully Fried.
While not usually acquired until between the ages of 2.5 and 3.5 years, I'm still pushing him, as it's one of the harder sounds for children with hearing loss to master. His /f/ comes out as a /p/ (which is helpful in some cases). We've been working on various oral/motor exercises, like playing with our bottom teeth, and using them to scrape off frosting a pudding from our lips. I've been over-emphasizing the initial /f/ sound, and we've even been using some pages out of this cool workbook to work on the sound.
I'm a little frustrated with all of this because Christian can totally produce the /v/ sound...the /f/ is pretty darn close. And I'm totally blaming this whole /f/ issue on why I can't lose the last 8 pounds of my pregnancy weight. Let's just say we get a lot of practice saying FIVE GUY FRENCH FRIES.