Regular

Regular
 

Para decir regular en inglés además de "so so" existe otra expresión o palabra?

Ejemplo.:
Cómo es tú inglés? - Regular.
Qué tal tocas el piano ? -Regular.

(It's) passable
mediocre/average
fair
not so bad
neither here nor there
nothing to write home about

SO if I say, can you play the piano?

You answer (regular)
(It's) passable
mediocre/average
fair
not so bad
neither here nor there
nothing to write home about

Not for that question.

Answers to your question:
"I'm fair at it."
"So, so"
"I'm average"

The other phrases listed by Rusty can be used with this question:
How was the food?

"It was passable.", "Not so bad", "Fair", "Nothing to write home about", "Average", "mediocre"

All of those phrases above mean the food was "average."

thank you.