Tim Bowen makes a breakthrough in explaining the sometimes confusing phrasal verbs associated with this word.
Reflecting on Usain Bolt’s sensational performance in the 100 metres at the Beijing Olympics, one reporter wrote ‘Imagine what he might achieve if he broke into a trot’. This use of break into to mean ‘to start doing something' is restricted to a few basic areas. Apart from a trot, you can also break into a gallop, a jog or a run, all of which might cause you to break into a sweat. Away from physical exertion, you might also break into song, laughter or applause. In business, a company will often try to break into (penetrate) a new market, while in terms of personal finances it might sometimes be necessary to break into your savings (start to use an amount of money) to pay for an unexpected expense.
All of this is a long way from the main meaning of break into, which is to enter a building by force, normally in order to steal something, as in 'A house in our street was broken into last night'. If arrested, the perpetrator of a break-in might well be sent to prison and might want to break out (escape). Apart from prisoners, fires, diseases and wars can also break out (start), as can sweat (again), as in ‘Sweat was beginning to break out on his forehead' and rashes, as in 'The skin on my arms was breaking out in a rash’.
Confusingly, talks or negotiations can break up without success and can also break down, as in ‘At one point the talks seemed close to breaking down’, with more or less the same meaning. If a person breaks down, they start crying, especially in public, as in ‘Many people broke down and wept'. Usain Bolt didn't break down when he won his gold medal. On the contrary, he broke into a smile, which was entirely understandable as he had just become the first man to break through the 9.7 second barrier for the 100 metres.