Shares of voice recognition specialist Nuance Communications (NASDAQ:NUAN) are having a good day, with shares gaining upwards of 9% on news that activist investor Carl Icahn has taken a stake in the company. The famed investor disclosed a 9.3% passive stake in Nuance, an indication that he believes shares are currently undervalued.

There are numerous possibilities on how Icahn could seek to restructure Nuance. Some analysts believe that Icahn could push for Nuance to strengthen its balance sheet, since it currently carries a large amount of debt due to its acquisitive nature. At the end of 2012, Nuance was sitting on more than $2.3 billion in long-term debt.

Since Nuance has so many businesses, it's also conceivable that Icahn would be looking to divest some of the less important segments in order to focus on its core licensing businesses in health care, mobile, and enterprise. For example, the imaging sector was just 12% of sales last quarter, and could potentially be divested.

Nuance got crushed two months ago when it reported earnings and issued soft guidance for the full year. That sell-off brought shares to 52-week lows and was likely overdone. CEO Paul Ricci cited macro headwinds in Europe as contributing factors to the conservative outlook.

Meanwhile, Nuance's valuation has always been a tricky topic, since its intangible amortization and other acquisition related costs put a drag on reported earnings and made its trading multiples appear inflated.

The fact that Icahn is buying in may give investors more confidence that Nuance isn't overvalued at 39 times earnings.

Ricci is a notorious hardball, as is Icahn. I'd gladly pay a cover charge just to watch those two duke it out in a boardroom. I also wouldn't be surprised if Ricci acted quickly to institute some anti-Icahn measures like a poison pill, a move other companies have made in the past to fend off Icahn's unsolicited advances.

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