Because the data is collected from natives of rural areas. The people are shown pictures to identify or are given sentences to complete with a particular word, Although every word has a unique isogloss, boundary lines of different words coalesce in some locations to form regions.
An isogloss in a linguistic atlas represents a boundary line that separates regions where different linguistic features are present. It is used to show dialectal variations within a language or language family.
isogloss
the boundary of people saying lift and elevator.
Geography.
No executive branch
no executive branch
ma troytyyyy
Blues artists were traveling musicians, making it difficult to establish a permanent address
Teens who establish strong relationships with positive role models seldom abuse drugs or alcohol. It's difficult to establish a relationship with someone over the Internet. Once you establish new friendships, you won't miss your old school so much.
Maybe, their could be Tsunami's, earthquakes and maybe volcano explosions.
Blues artists were traveling musicians, making it difficult to establish a permanent address.
all of the above