The Dow Jones Industrial Average closed down 53.72 points, or 0.29 percent, at 18,232, with Boeing leading laggards and Goldman Sachs and Apple the greatest advancers.  The S&P 500 closed down 4.75 points, or 0.22 percent, at 2,126.07, with telecommunications the greatest of nine laggards and information technology the only advancing sector.  The Nasdaq closed down 1.43, or 0.03 percent, at 5,089.36.  The CBOE Volatility Index (VIX), widely considered the best gauge of fear in the market, traded near 12 after hitting a year-to-date low of 11.82.  Read MoreMarket volatility hits 2015 low  Nearly two stocks declined for every advancer on the New York Stock Exchange, with an exchange volume of 617 million and a composite volume of 2.5 billion in the close.  Crude oil futures for July settled down $1.00 at $59.72 a barrel on the New York Mercantile Exchange, marking the 10th positive week in a row. Data going back to 1983 does not show a longer stretch of consecutive gains.  Gold futures settled down 10 cents at $1,204.00 an ounce.  Microsoft and Salesforce had significant talks about an acquisition but failed to reach a deal on price differences, sources familiar with the situation told CNBC.  Earnings out on Friday included Campbell Soup, Deere, Foot Locker before market open.  Lions Gate Entertainment earnings came in 7 cents above estimates with adjusted quarterly profit of 39 cents per share, but revenue fell considerably below analyst forecasts.  BlackBerry will buy back about 2.6 percent of its outstanding shares, to negate potential negative effects of a proposed employee stock purchase plan.  Hewlett-Packard reported adjusted quarterly profit if 87 cents per share, 2 cents above estimates, though revenue was slightly shy of forecasts. The company also issued weaker-than-expected current quarter guidance. Investors are taking note of a positive development—lower-than-expected expenses for the separation of its personal computer and printer businesses into a separate company.  Deere & Co. earned $2.03 per share for its latest quarter, beating estimates of $1.55 despite a slight revenue shortfall. Deere noted a weak global agricultural sector, but said good execution aided its bottom line.  Foot Locker beat estimates by 6 cents with earnings of $1.29 per share. Revenue and same-store sales were above analyst forecasts, and the company said the quarter was the most profitable in its history.  Campbell Soup earned an adjusted 62 cents per share for its latest quarter, 10 cents above estimates, though revenue fell short due to currency effects. Campbell said its full-year sales would fall towards the lower end of its projected range, but earnings would be at the more favorable end.  Read MoreEarly movers: DE, FL, CPB, HPQ, GPS, ROST & more  European equities closed mixed on Friday as investors focused on a central bank meeting in Portugal and Yellen's speech.  Mario Draghi, president of the European Central Bank (ECB), spoke at the event in Sintra, Portugal earlier Friday. He said that the economic outlook for the euro zone is looking "brighter today than it has done for seven long years."  China's Shanghai Composite gained 8.1 percent for the week, its strongest since the week ending December 5, 2014, when it rose 9.5 percent.  The S&P 500 ended mildly higher on Thursday above its previous record close of 2,129.20 to post its 10th closing high for the year.  "Investors are going into this weekend knowing there isn't any catalyst to force the Fed to move anytime soon and that means we're all data-dependent," said Adam Sarhan, CEO of Sarhan Capital.  Durable goods orders and another read on first-quarter GDP come out next week.  —Reuters and CNBC's Patti Domm and Peter Schacknow contributed to this report.
U.S. stocks closed lower on Friday as investors eyed inflation data and Fed Chair Yellen's speech ahead of the long weekend.