LACONIA, N.H. -- Jeb Bush opted not to hammer Donald Trump too hard over his flubbed foreign policy test Thursday afternoon.

Instead, the former Florida governor drilled the early frontrunner in Republican 2016 polling over his criticism of Bush for speaking Spanish during interviews and for using language, he alleged, that serves as a "dog whistle" to racists.

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Answering a question, Bush said that people who immigrate to the U.S. "need to learn English, but that doesn't mean they stop speaking their native tongue."

Then, he went further.

"Perhaps even more offensive was the notion that somehow I went down to the border and spoke Mexican," Bush said, referring to Trump's reaction to his visit last week to McAllen, Texas. "Those are dog whistle terms; he knows what he's doing. These are very divisive terms. If we're going to win elections, we need to be much more open, open and optimistic, rather than sending signals that prey on people's angst."

Bush, who has now incorporated his multi-faceted argument against Trump into his stump speech, showed far more fire during his hour-long event inside a sultry VFW post here than he did during a town hall Thursday morning inside a manufacturing plant in Hampton.

After a woman asked if he was worried about sharing the fate of other GOP candidates who have attacked Trump hard only to fade in the polls, Bush said he's wasn't looking for a fight but isn't about to shy away from one given Trump's persistent needling and often personal attacks.

"When he attacks me personally or disparages my family, you're damn right I'm going to fight back," Bush said.

Following the town hall, Bush again pushed back at a reporter who suggested he was "stepping up" his attacks.

"I'm just responding to the personal diatribes that come my way," he said, noting that being in fighting mode doesn't mean he can't continue to campaign in the joyful manner.

"You can be joyful and tough," he said, firmly. "That's what I am."