Benefit

You can use any druid or ranger spell that normally targets animals against vermin as well. A mindless vermin is considered to have an Intelligence score of 2 when dealing with you, and can be charmed, calmed, or targeted by wild empathy or similar abilities.

In addition, you gain the ability to speak with vermin as a spell-like ability usable once per day (caster level 1st). This is identical to speak with animals, but can be used only with vermin and vermin swarms.