Default custom rom


I just bought a DVP and there is no Hebrew language inside so I decided to update the WP7.5 but i have few questions:

1. Is there a way to find heb language without a custom rom? if so where can i find it and how to install it?

2. if not? Where can I find instructions, how to install custom rom for the DVP and which custom rom is the best and support heb language?

3. if i'm installing a custom rom does it mean that i jailbreak my DVP?