IJ (digraph)

IJ (lowercase ij; Dutch pronunciation: [ɛi]) is a digraph of the letters i and j. Occurring in the Dutch language, it is sometimes considered a ligature, or even a letter in itself – although in most fonts that have a separate character for ij the two composing parts are not connected, but are separate glyphs, sometimes slightly kerned.

An ij in written Dutch usually represents the diphthong [ɛi]. In standard Dutch, and most Dutch dialects, there are two possible spellings for the diphthong [ɛi]: ij and ei. This causes confusion for schoolchildren, who need to learn which words to write with ei and which with ij. To distinguish between the two, the ij is referred to as the lange ij ("long ij"), the ei as korte ei ("short ei") or simply E – I. In certain Dutch dialects (notably West Flemish and Zeelandic), as well as the Dutch Low Saxon dialects of Low German, a difference in the pronunciation of ei and ij is maintained. Whether pronounced identically to ei or not, the pronunciation of ij is often perceived as being difficult by people who do not have either sound in their native language. The tendency for native English speakers is to pronounce ij as [aɪ] (like the English vowel y, as in by) which does not normally lead to confusion among native listeners, since in a number of dialects (e.g. in Amsterdam, home of the body of water called the IJ) the same pronunciation is heard.

...
Wikipedia