What weighs more; an African elephant or a blue whale's tongue?

If you mean which tongue is heavier, a blue whale's tongue weighs around 2.7 tonnes https://www.scifacts.net/animals/blue-whale-tongue-size , while an elephant's weighs 12 kilograms (0.012 tonnes), so a blue whale's is a lot heavier.

However, an elephant itself is a lot heavier then a blue whale's tongue!

"Both African elephant species are bigger than the Asian Elephant. Males stand 3.6 m (12 ft) tall at the shoulder and weigh 5,400 kg (12,000 lb), while females stand 3 m (9.8 ft) and weigh between 3,600 and 4,600 kg (7,900 and 10,000 lb). However, males can get as big as 6,800 kg (15,000 lb)."

2.7 tonnes for a blue whale's tongue, as per Redwallcraxy's post, is about half the weight of an adult make African elephant, at 5.4 tonnes.
https://en.wikipedia.org/wiki/African_elephant