* Dollar index languishes near 3-1/2 week lows
* Pullback in U.S. 10-year yield weighs on dollar -analyst
* Commodity currencies remain firm, Aussie hits 2-month high
SINGAPORE, Dec 28 (Reuters) - The dollar was on the defensive on Thursday, facing headwinds from a dip in U.S. 10-year bond yields, while commodity-linked currencies were bolstered by this week's rally in metal and oil prices.
The dollar's index against a basket of six major currencies last stood at 92.980, languishing near Wednesday's trough of 92.956, its weakest level since Dec. 1.
"Bond yields have pulled back from their peaks and the dollar is trading with a soft tone," said Satoshi Okagawa, senior global markets analyst at Sumitomo Mitsui Banking Corporation in Singapore, referring to a pullback in U.S. 10-year Treasury yields.
The U.S. 10-year Treasury yield stood near 2.42 percent , having come off a nine-month high of 2.504 percent set last week. The U.S. 10-year yield had slipped on Wednesday as investors rebalanced portfolios before year-end.
The euro edged up 0.1 percent to $1.1902, having set a 3-1/2 week high of $1.1911 on Wednesday.
Against the yen, the dollar eased 0.2 percent to 113.19 yen , staying below a four-week high of 113.75 yen touched on Dec. 12.
Currencies of commodities exporters remained firm, in the wake of this week's rise in oil prices to 2-1/2 year highs and a surge in copper prices to four-year peaks.
The Australian dollar touched a fresh two-month high of $0.7780 on Thursday, having gained 0.8 percent so far this week.
The Canadian dollar last stood at C$1.2639. On Wednesday, the loonie had touched a three-week high of C$1.2627.
A rise to levels beyond its early December high of C$1.2624 would send the Canadian dollar to its highest since late October. (Reporting by Masayuki Kitano; Editing by Sam Holmes)