G. Sumerian Pictographs and Egyptian Hieroglyphs as Syllabic Signs
An examination of comparable Sumerian pictographs and Egyptian hieroglyphs as syllabic signs seemed logical given the legends relating to Greek letters, which suggest a foreign origin to Greek script.
If it were possible that the Minoan Aegean signs were similar to Old Elamite script, i.e. an ancient connection by sea to Elam (today's Iran) via merchant trade, then some ancient relationship to Sumerian signs in the Ancient Near East was also possible. Moreover, given the legend of Cadmus bringing the Greek letters to Greece via Egypt, it seemed worthwhile to also look at comparable Pharaonic hieroglyphs.
In this connection various online sites were used as resources. A glossary of Sumerian terms is found e.g. at the ETCSL (Electronic Text Corpus of Sumerian Literature) but that source is very weak because it does provide the original signs -- so that one can not check whether transcriptions and transliterations are correct.
Patrick C. Ryan  provides a Sumerian Archaic Sign Table and a Sumerian Sign Value Register as well as Proto-Language Monosyllables with Correspondent Sumerian and Egyptian Signs, all of which are quite valuable as resources for the signs themselves, although I sometimes disagree strongly with the analysis given by Jaritz and Ryan to the meanings and origins of the signs, some of which are better clarified here through an analysis of comparable Minoan Aegean signs. Nevertheless, given the dearth of sign materials online for Sumerian, Ryan's online resources are of significant importance for providing essential Sumerian materials and he must be commended for recognizing that these signs and symbols are related to other languages of the world. Sumerian signs are cited to their Jaritz number. Ryan writes:
"The sign numbers are those of Jaritz' Schriftarchäologie der altmesopotamischen Kultur (1967). Unfortunately, the register materials in this book were not carefully proofed before publication so an unknown number of errors are present. I have made many corrections as I have found them but there are undoubtedly more errors present. Where I have discovered a questionable sign number assignment for a reading, I have placed a question mark after it. In some cases, the sign reading or its proper subscript may be in question, or the subscript may not be known by me, which sign reading also bears a question mark."The Wikipedia has numerous pages on Egyptian hieroglyphs, see e.g. Gardiner's Sign List, the A-L list and M-Z list. Other resources are cited when used in this text.
 It was on Patrick C. Ryan's suggestion that I started the online group ACE (Ancient Cultures Explored) in 1997 to replace the defunct ANE list at the University of Chicago. ACE was changed in 1999 to the LexiLine list, which still exists today online, primarily as a newsletter on the History of Civilization. See http://tech.groups.yahoo.com/group/LexiLine/message/595 and http://tech.groups.yahoo.com/group/LexiLine/message/1403 and