Newton's third law is that for every action there will be an equal and opposite reaction. In Northern Ireland that translates as, for every tribal insult there will be an equal and opposite tribal insult.

And so it was in recent days. The DUP again insults the Irish language and by implication people who have regard for it. Sinn Féin in turns insults unionists. Yes, we know there were qualifications from Gregory Campbell and Gerry Adams but that is how their comments were viewed by many people.

The big surprise this time is that it was the Sinn Féin president who was engaging in retaliatory invective. Normally he has the wit to steer clear of such sectarian in-fighting; if there is a requirement for roughhouse verbal invective across the community divide it would be for Sinn Féin people much lower down the command chain to do the insulting.

It was odd that the Sinn Féin president should be so cack-handed unless he was deliberately trying to stir it up. Whichever, Peter Robinson and the DUP must have been saying prayers of thanks that, however temporarily, he got the party off the hook on which Gregory Campbell had impaled them.

And as the saying goes, if it wasn’t so serious it would be funny. For instance on Monday the Sinn Féin Minister for Education John O’Dowd said if a Sinn Féin politician had been as deliberately disrespectful as was Gregory Campbell of someone else’s culture Martin McGuinness would sack him. Is the Deputy First Minister now going to dismiss the Sinn Féin president?

At the weekend annual conference with great premeditation East Derry MP Gregory Campbell again repeated his sleight on the Irish language with more references to “curry my yogurt”, his phonetic take on “Go raibh maith agat”.

Through the DUP press office, and therefore with the imprimatur of the Peter Robinson leadership, Campbell's speech contained the line, "On behalf of our party let me say clearly, and slowly so that Caitriona Ruane and Gerry Adams understand, we will never agree to an Irish language act at Stormont and we will treat their entire wish list as no more than toilet paper. They better get used to it."

Yet at the same conference the DUP had also invited Dr Micheal O Duibh, chief executive of the Irish language school sector in Northern Ireland to make his case for the language.

Figure that: on one hand the DUP is pumping up the derision while on the other hand it seeks to reach out to Irish language speakers.

Robinson was dismissive of criticisms of Campbell, referring to annual conference “comedy” which is different than politics in regular time, while Campbell and the DUP generally contended that the insult wasn’t against the language but how Sinn Féin “abused” it.

But equally Robinson and the DUP would have realised full well that ordinary nationalists and Irish speakers viewed this as yet another sectarian DUP attack which undermined all the grand talk of reaching out to the other side. Too many mixed messages.

But then with his “break these bastards” comments in Enniskillen Gerry Adams managed to shift the DUP from the back foot to the front foot.

He said: “But what’s the point? The point is to actually break these bastards - that’s the point. And what’s going to break them is equality...That’s what we need to keep the focus on - that’s the Trojan horse of the entire republican strategy is to reach out to people on the basis of equality.”

Later Adams issued a "mea culpa" tweet, saying he was referring to "bigots, racists and homophobes" and not to unionists specifically. He also apologised for his "bastards" remark. But who were these "bigots, racists and homophobes"? As far as unionists such as the DUP Minister Arlene Foster and the Ulster Unionist leader Mike Nesbitt were concerned Adams' remarks were directed against the unionist people in general.

They also focussed on the “Trojan horse” element of his remarks, as did the SDLP. They characterised it as Adams and Sinn Féin using the issue of equality, not as a good thing in itself, but as a sinister tactic to undermine unionism and cause political instability. According to Nesbitt it was a return to 1997 remarks by Adams which were interpreted as Sinn Féin with malice aforethought exploiting parades for the exact same purposes.

All this sourness is happening as the British and the Irish governments and the five main parties are trying to reach an agreement to keep the Northern Executive and Assembly functioning. That deal must happen by Christmas as the North will be into pre-British general election campaigning in the new year.

This latest bout of recrimination won’t improve the odds of success or the negotiating atmosphere.