What is the translation of word how come in tagalog?

There isn't a direct one-word translation for "how come" in Tagalog. You'll need to use a phrase depending on the context. Here are some options:

For asking about a reason:

* Bakit? (Why?) - This is the most common and direct translation.

* Paano nangyari? (How did it happen?)

* Ano ang dahilan? (What is the reason?)

* Ano ang pangyayari? (What happened?)

For expressing surprise or disbelief:

* Paano nangyari 'yun? (How did that happen?)

* Talaga? (Really?)

* Bakit ganun? (Why is that?)

* Hindi ko maintindihan. (I don't understand.)

The best translation depends on the specific situation and the tone you want to convey.