When the 接続助詞（せつぞくじょし） (conjunction particle) たら
is used before the 副詞（ふくし） (adverb) どう, it primarily presents a situation, then asks a question about it potentially happening. This construction can be translated as ‘why don’t you (A)?’, or ‘what if you did (A)?’. Realistically, it just means ‘when (A), how about that?’. It is often used for giving advice.
To use this expression, convert the verb that you want to use into its たら
form, and then add どう.
is used by itself, with a tone that implies that it is a question (or simply by adding a question mark in written language). This is an abbreviation of たらどう
, and carries the same nuance.
may be added to the end of たらどう
, to emphasize the ‘question’ even further. However, they are not required.
Why don't you try calling the police?
If it is bitter, why don't you add some sugar?
Despite being used for giving advice, たらどう
may be interpreted as criticism. Due to this, care will need to be taken with your tone of voice.