"Loosen someone's tongue" is an idiomatic phrase that means to make someone more talkative or reveal information that they might otherwise keep secret. However, if you're looking for other ways to express this idea, there are several synonyms available. One could say "encourage speech," "stimulate conversation," or "draw out information." Other options include "coax disclosures," "prompt confessions," or "woo confidences." Each of these phrases conveys a similar sense of trying to elicit information or encourage someone to share their thoughts, making them useful alternatives to "loosen someone's tongue".
