There is

  a

Determiner

  proven

Verb

  Basque

Adjective

  substrate

Noun

  in

Adposition

  the

Determiner

  development

Noun

  of

Adposition

  Gascon

Proper noun

.

There is a proven Basque substrate in the development of Gascon.

There is a proven Basque substrate in the development of Gascon.