DynaVox, which offers proprietary software to assist people with speech, language and learning disabilities, filed on Tuesday with the SEC to raise up to $125 million in an initial public offering. The Pittsburgh-based company booked $91 million in sales over the last 12 months and plans to list on the NASDAQ under the symbol DVOX. Piper Jaffray and Jefferies are the lead underwriters on the deal. Pricing terms and timing were not disclosed.