In Westeros everyone South of the Wall speaks the same language 'The Common Tongue', but surely we should see at least 4 distinct languages being spoken at least by the small folk.
The 'Old Tongue' in the North The 'Common Tongue' in the South Dornish in Dorne The 'Iron Tongue on the Iton Islands
The 'Old Tongue' in the North The 'Common Tongue' in the South Dornish in Dorne The 'Iron Tongue on the Iton Islands