Here are a few "Tiger tongues" from Laos. The first time I saw them, I thought they looked like a fully opened crocodile's mouth so I wondered what was meant by tiger tongue. But, I've never been close enough to see what a tiger's tongue looks like or a crocodile's mouth, so who knows?
These would cover 1645-1795, according to Howard Daniel, and are silver progressing to billon to mostly copper. Actually, you can sorta timeline them based on silver content and markings. The two smaller pieces on the right are the oldest. As they move towards the 1860s, the debasement of the pieces gets to the point where the mid 1800s pieces look entirely copper. I have some pieces from the early 1800s, but they do not have characters stamped on them, and they are more copper than anything else. They are not illustrated in the picture. The mostly copper pieces are the last before the boat/canoe money in 1865.
