In the standard view, open office writer will show with red marker at the bottom of a text when that text is misspelled or mistyped. But I forgot when I disable it. Even when I run autocheck, the marker is not show up. So this must be something funny.

I opened the Tool – Option
Go to Language Setting – Writing Aids…

And find out that the available language module is empty. Is this the cause? So I went to openffice site to find some dicitionary and download en_US.oxt and save it to my computer.

Then go to Tools – Extension Manager – Adds
search for the en_US.oxt that I just downloaded. And now the red mark shows again when I  mistype my word.