Simplify the following text for a Grade 10 native English-speaking person.
Original: Thought to be comparable to the old Land Spaniel , they are similar to the English Springer Spaniel and historically have been referred to as both the Welsh Spaniel and the Welsh Cocker Spaniel .
Simplified: They are similar to the English Springer Spaniel and historically have also been called the Welsh Spaniel and the Welsh Cocker Spaniel .