Cable, Thomas. "Language, History of the." In Medieval England: an encyclopedia, edited by Paul E. Szarmach et al., 405-410. New York : Garland Pub., 1998. HOLLIS Record
Gneuss, Helmut. "The Old English language." In The Cambridge companion to Old English literature, edited by Malcolm Godden and Michael Lapidge, 23-54. Cambridge; New York: Cambridge UP, 1991. HOLLIS Record. Also available online in the Cambridge Collections Online series [Harvard ID required]
Hoover, David L. "Old English language." In Dictionary of the Middle Ages, edited by Joseph R. Strayer, vol. 9, 226-231. New York : Scribner, 1982-1989. HOLLIS Record
Robinson, Orrin W. 1992. Old English and its closest relatives. Stanford: Stanford UP, 1992. HOLLIS Record (see chapter on Old English (p. -175).
Historical grammars of Old English describe and explain the development of OE from its prehistoric origins (Proto-Indo-European --> Proto-Germanic --> West Germanic --> pre-Old English) through the attested OE period (ca. 650 to 1066).
The standard English-language historical grammar of OE has long been Alistair Campbell, Old English grammar (Oxford, 1959). HOLLIS Record
An important complement to Campbell is Richard M. Hogg, A grammar of Old English (2 vols, Blackwell, 1992-2011). Volume 1 (Phonology) and Volume 2 (Morphology, co-authored by R.D. Fulk) provide modern treatments of these subjects, with extensive bibliographies. [WID-LC PE131 .H6 1992] HOLLIS Record
The prehistory of Old English is covered in detail in Donald Ringe, ed., A linguistic history of English: from Proto-Indo-European to Proto-Germanic (Oxford, 2006). [WID-LC PE1075 .R55 2006] HOLLIS record (full text available online via HOLLIS, Harvard ID required)
The standard German-language handbook is Karl Brunner, Altenglische Grammatik; nach der Angelsächsischen Grammatik von Eduard Sievers (3. Aufl., 1965, Niemeyer). [WID-LC PE131 .B78x 1965] HOLLIS Record
The most reliable and detailed survey of English historical phonology, including the development of OE, is Karl Luick, Historische Grammatik der englischen Sprache (Vol. 1, Pts 1-2, 1914-1940; Harvard UP reprint, 1964). [Widener 9275.11.13] HOLLIS Record (full text available online via Internet Archive)
Much of Luick's coverage has been summarized conveniently by his student, Hans Pinsker, in his Historische englische Grammatik (2. Aufl., Hueber, 1963). [Widener 9276.53.2 ] HOLLIS Record
Still valuable as a concise historical grammar of OE is Ernst Kieckers, Altenglische Grammatik (Hueber, 1935). [Widener 9286.32.50] HOLLIS Record