Keyword Analysis & Research: what is two dots over a letter called

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
what is two dots over a letter called	0.89	0.8	4964	76	37
what	0.85	1	4465	99	4
is	0.23	0.2	7186	84	2
two	1.98	0.6	1967	62	3
dots	1.95	0.1	7059	99	4
over	0.54	0.2	1590	2	4
a	1.92	0.8	1749	3	1
letter	2	0.2	6881	96	6
called	0.89	0.3	8543	68	6

Keyword	CPC	PCC	Volume	Score
what is two dots over a letter called	1.99	0.2	4858	13