Begin and start both refer to the beginning of an action which is going to be performed. Begin is an irregular verb (Present begin, Past began & Participle begun) whereas start is regular and has its past and participle started.
Most etymologists and grammar books suggest that begin and start are interchangeable and there is no real difference in meaning and it all depends on the context where one word may differ with other. However, if we exhaustively analyse both words, there are some striking differences between them – one form (or the other) can be used in some particular situations.
To make life easier, we must affirm that in some particular situations, one specific word is to be used.
Begin: shows that the subject is carrying out the first or earliest part of an action which will be going on for a while. Begin is followed by a noun, a verb in the –ing form or a verb in the infinitive. In formal writing, begin is more desirable than start:
In the latest India New Zealand match, India had just begun playing their match when rain god played spoilsport.
Notice that with begin, the action is very often quite formal:
The President has begun to congratulate the winning teams.
Start: less formal than begin. Start is also followed by a noun, a verb + ing, or an infinitive, in the same conditions as begin. Start is also used in some particular ways – to come into movement, into being in operation, for a machine:
Can you start the generator while I start cleaning the stable?
Jeff Bezos started his company Amazon from his own garage.
He started his consulting business in 1980, after working in the Capital Development Office of the Department of Commerce.
Be careful! After an -ing form, do not use begin/ start+ a second verb in the -ing form. Instead, use the infinitive form.
Frank is beginning driving very quickly and well now. ✗
Frank is beginning to drive very quickly and well now. √
Some more example sentences
When did she begin/start learning French?
The matinee show didn’t begin/start until 2 pm.
Jane is having trouble beginning the printer. ✗
Jane is having trouble starting the printer. (means it doesn’t work) √
They began their family business, a mining company, and it’s been going really well. ✗
They started their family business, a mining company, and it’s been going really well. √