It’s not a dialect thing, the river is literally called “River Wear” irrespective of your accent or dialect. Plymouth (Plih Muth) and Tynemouth (Tyne Mouth) are

It’s not a dialect thing, the river is literally called “River Wear” irrespective of your accent or dialect. Plymouth (Plih Muth) and Tynemouth (Tyne Mouth) are pronounced completely differently and I don’t call Plymouth “Ply Mouth” just because I live near Tynemouth.