Word square place names). However, 11-squares are possible if words from a number of languages are allowed ("Word Ways", August 2004 and May 2005). It is possible to estimate the degree of difficulty of constructing word squares. 5-squares can be constructed with as little as a 250-word vocabulary. Roughly, for each step upwards, one needs four times the number of words. For a 9-square, one needs over 60,000 9-letter words, which is practically all of those in single very large dictionaries. For large squares, the vocabulary prevents selecting more "desirable" words (i.e. words that are unhyphenated, in common use, without contrived inflections,
English words of Greek origin to recognize words of Greek origin, and give hints as to their pronunciation and inflection. Some romanizations are not completely standard. The Ancient Greek diphthongs and may be spelled in three different ways in English: the digraphs "ae" and "oe"; the ligatures "æ" and "œ"; and the simple letter "e". The ligatures have largely fallen out of use worldwide; the digraphs are uncommon in American usage, but remain common in British usage. The spelling depends mostly on the variety of English, not on the particular word. Examples are: "encyclopaedia" / "encyclopædia" / "encyclopedia", "haemoglobin" / "hæmoglobin" / "hemoglobin", "oedema" /