Learn Portuguese (Portugal): Esperem lá pela batida para o arranque.

In this sentence, lá is not a location marker. Instead, it acts as a pragmatic mitigator. By adding lá to the imperative Esperem, the speaker softens the command, making it sound more like 'just wait' or 'wait a sec' rather than a strict order. It gives the instruction a more casual, conversational tone.

Why is it pela batida and not para a batida if it means 'wait for the beat'?

When the verb esperar means 'to wait' for a noun, it requires the preposition por. Because batida is feminine, por combines with a to make pela. English speakers often mistakenly use para because it directly translates to 'for', but in Portuguese, esperar para is generally only used when waiting to do an action, followed by another verb (like esperar para ver, meaning 'to wait to see').

I usually use início or começo for 'start'. When should I use arranque instead?

The noun arranque comes from the verb arrancar (to pull away, start an engine, or take off). It implies a sudden, energetic, or dynamic start, like a burst of movement in a race or the drop of a beat in music. Words like início or começo simply mean the beginning in a neutral way, without that sense of physical momentum.