Talk of a double-dip recession is growing louder, and some market experts are finding fewer reasons to stay bullish as recovery slows to a crawl.

There are still more optimists than pessimists, but even economists and strategists who don't see the economy going into a steep second slide are hinting that the recovery will remain slow through the summer. As Richard Ross of Auerbach Grayson noted on Wednesday, "the 'double dip' debate hasn t been this heated since George Costanza committed the infamous breach of party etiquette on the fourth season of 'Seinfeld.'"

That debate has played itself out in the grim market volatility of the past two months, with the S&P 500 index dropping from 1171 on May 12 to 1022 on July 2, a 12.7% slide. The Dow Jones Industrial Average had a similar 11.1% slip in the same period. Stocks have rebounded somewhat since then, but investors remain nervous.

As the immediate benefits of government stimulus fade, concern is mounting over the private sector's ability to create jobs and spur the pace of the business cycle. Tepid jobs growth prompted New York University economist Nouriel Roubini to point out Wednesday that "the recovery is failing to give signs of self-sustainability."

John Hussman, president of Hussman Econometrics Advisors, weighed in for the downsiders. After an "almost inconceivably large burst of fiscal and monetary "stimulus'" last year, the expected soft patch is stretching to the point where "the U.S. economy is most probably headed into a second leg of recession. It is unclear whether this will be identified as a second recession or a continuation of an existing downturn."

David Rosenberg, chief economist at Gluskin Sheff and a longtime bear, said Thursday that the technical measures that would put the economy once again into recession are almost secondary now.

"The major point is that, at the margin, double-dip risks are rising and the odds of a V-shaped recovery are fading," he wrote. "What is more important is that the U.S. economy is very fragile and more vulnerable" to another disruption of the slow recovery.

Not everyone is convinced a second dip is imminent.

Chris Maxey, a senior analyst at asset manager Fortigent, said Tuesday that a longer view is needed. "The signs of a double-dip recession are simply not there yet," he wrote. "Slower growth is a given at this point, but this should not come as a surprise considering that it has been well-documented that previous stimuli would become a detractor to growth in the second half of 2010 and through 2011."

Societe Generale global head of economics Michala Marcussen said in a Tuesday report that although it was necessary to cut the bank's 2010 U.S. growth outlook from 3.7% to 3.1%, the new forecast was symptomatic of a "stuttering recovery, not a double dip."

An exasperated Brian Wesbury and Robert Stein, chief economist and senior economist, respectively, at First Trust Advisors, said recent pessimism ignores genuine support for even a slow moving recovery. In a Tuesday commentary lashing out at critical dissections of the recent jobs report, they expressed amazement that 83,000 new private sector jobs were seen as a setback.

"Pessimism has become so pervasive that people will believe just about anything, as long as it is negative," they wrote. "This is a complete overreaction and is indicative of the severe case of economic hypochondria that seems to have gripped the nation and the world."