The quote "Valleys have ears and some elves have over merry tongues" suggests that one should be cautious about what they say, as secrets or private conversations can easily be overheard, especially in seemingly innocent or open places. The mention of "elves" with "over merry tongues" implies that certain beings, possibly mischievous or whimsical, may delight in spreading gossip or secrets. Overall, the phrase serves as a reminder of the importance of discretion and the potential consequences of loose talk.