how to tell Google that these pages are updated?

Hi,

I used some english language pages on my website some weeks before and all pages are indexed in google.

since two weeks these pages are translated (using the same URL's) into the dutch language.

I'm using a sitemap and the google checks my site frequently, but the pages are still not updated in google.

is there something I can do get this faster?

Put the new versions on different URLs then do a 301 redirect to the new version, also make sure you have changed the language doctype accordingly.

You can also trackback. I am not sure if this will work for this situation, but if you have an rss feed try pingoat.com or a similar service.

and this will help in google?

I think redirecting is not bad since there is almost no traffic on these pages at the moment

Trackback helps with google because it is frequently crawling all the blogging related sites like technorati.