How to handle Translation in twig file using variables?

Question

You were going on right track, what you missed is just to pass someVariable as a parameter to trans() in your Twig file as:

<h2>{{ "follow.us.in.twitter"|trans({'%someVariable%': someVariable}, "workend") }}</h2>

Now your message in Yml file should be as:

follow.us.in.twitter: Hola, Follow %someVariable% en Twitter

This should work.
For more details and clarity you can refer the following:
Symfony Book

Good Luck.