By default Google Play is configured to display reviews only in my native language (not english). But there are a lot of reviews in other languages, especially in english and I want to see them also. As a workaround I can change language to english but it is not perfect solution. Can I see reviews both in my native language and in english?
Not with the regular Playstore app, AFAIK.
If you want to do so using an app, you might want to take a look at Market Comments Reader. From within the web browser, AndroidPIT allows to show comments of all languages at once, i.e. without selecting each language separately.
Update: note that both, the app and the AndroidPIT site section, are dead by now. For a work-around you could use my UserScript GooglePlaySwitchLang in a web browser (like Firefox) via an Addon like Greasemonkey (see the Greasyfor main page for a list of options for your favorite browser). The script injects links to easily toggle between languages – currently German and English, but you easily can adjust it to any language combination you need.