Nonrhoticity

The best-known features of ENE speech are its traditional nonrhoticity...

The occasional retentions are probably 'unresolved' variation from the input dialects, which must have been partly rhotic, as full nonrhoticity was not achieved even in southern English standards until the later nineteenth century...

This impression is due to certain segmental features (nonrhoticity, vowel quality), but also to sentence intonation patterns.