Well, if it's an ordinary bicycle with two wheels added to the side, then those extra wheels are called trainer/training wheels. It's a so-so way of teaching people to ride bikes w/o falling over.
For kids they usually prolong the learning period, as kids tend to support themselves on the trainers all the time instead of merely having them as a stop when they're about to topple over.
the term stabilisers is also used in addition to trainer wheels or training wheels
A wheel lift
tandem bicycle.
a pushbike
bicycle clip
A person who repair bikes is a bicycle mechanic. A shop that handles bikes is a bicycle shop or a bicycle store.
No. The first bike is usually considered to be the boneshaker AKA celefiere AKA draisienne. This was a very crude design that didn't have pedals, you simply straddled it and kicked yourself forward with your feet.
wheel or helm
In Kannada, we call them Dwichakra-vaahana.
bicycle bell in punjabi
A Confederate sympathyzer
supporting actor
A bicycle