For the duration, this spell grants the creature you touch the ability to understand any spoken language they hear, no matter if common, ancient or elemental.

Moreover, when the targeted creature speaks, any creature that knows at least one language and can hear the target understands what it says, as if the speaker would be of native tongue.

A creature that suspects the speaker of being influenced by this effect can make an INT (Investigation) or WIS (Insight) Check against your Spell Save DC. On a success, the creature realizes revealing mistakes in pronounciation, wording and general expression that give away the influence of this effect.