Stump (1984:293, n.2)

 "There are non-standard dialects of Breton in which the pattern of verb-inflection in negative clauses is the same 
 as that observed in affirmative clauses; for such dialects, (i) is acceptable and (ii) inacceptable.
 
 Trépos Grammaire bretonne (n.d. [1968]) is apparently based on a non-standard dialect of this sort; 
 cf. the example Ar selaouerien ne gleve netra, 'The auditors didn't hear anything' (p.266), 
 in which 'gleve' is in its analytic form [3SG]."
 

(i)	ar vugale	ne	lenn	ket	levrioù.
	The children	Ptc	read	not	books
	'The children don't read books.'

(ii)	* ar vugale	ne	lennont	ket	levrioù.
			read.PL
	'The children don't read books.'

référence

• Stump, G. T. 1984. 'Agreement vs. incorporation in Breton', Natural Language and Linguistic Theory, 2:289-348.