Old English (OE) brought with it many features of the West Germanic including fixed stress on the root syllable, dental preterite, phonemic length for consonants and vowels, compounding, different values for consonants from other PIE languages (Grimm's Law), a two tense verbal system, and a large word stock independent from PIE.  Thus, many of the features listed under "Internal Changes" for OE will be the same as the features in the list you just read.
 
 

 
 

Internal Changes/Features	External Events
Phonological	449-Germanic Migration Begins
Fixed Initial Stress	597-Christianization Begins
Addition of Phonemic Alveopalatal Africates	787-1042-Viking Invasions/Influence
and Voiceless Alveopalatal Fricative	878-Danelaw (Treaty of Wedmore)
Loss of Velar Fricatives	1000-Copy of Beowulf Survives
Morphological
Heavily Inflected (Synthetic):
3 noun declensions (case, number, gender)
10 verb conjugations (7 strong verbs)
strong/weak adjective declension
Dental Preterite
Syntactic
Preferred SVO Syntax
Adjectives often Follow Nouns
Semantic
Compounding & Affixation
Latin and Danish Borrowings

 
 

Elaboration: Culturally, England was a loose confederation of seven kingdoms (Northumbria, Mercia, East Anglia, Essex, Wessex, Sussex, Kent) called the Heptarchy. Literacy is largely non-existent, and many literate people use Latin (thus our alphabet is of Latin characters).  Thus, OE was by no means a unified, homogeneous language.  Multiple dialects existed, some of which were almost certainly mutually unintelligible.  The Danish influence north of the Danelaw preserved many Germanic features, especially phonological ones.  Written documents are often in the West Saxon dialect, which makes OE seem more stable than it is.
 
 

 
 

Internal Changes/Features	External Events
Phonological	1066-Norman Invasion
Inflectional Simplification (All Categories)	1337-1453-Hundred Years War
Addition of Phonemic Voiced Fricatives	1348-51-Black Death
Morphological	1400-Chaucer
Inflectional Simplification (All Categories)
Weakening of Phonemic Vowel Length
Syntactic
Reliance on SVO Syntax
Phrases Begin to Replace Inflections,
especially in Verbs
Semantic
French Borrowings (10,000 words added)
Compounding and Affixation

Elaboration:  Culturally, the Norman occupation resulted in a feudal society with French spoken at the top and English spoken at the bottom.  Widespread borrowing and bilingualism eventually led to the collapse of the inflectional system.  While some inflectional machinery certainly existed in ME, by the 1200s English largely relied on syntax.  Vowel length remains phonemic, but the loss of word final inflections begins to shorten vowels across the board.  The London dialect becomes the basis for standardization.  This is by far the period of greatest change in the history of English.

 
 

Internal Changes/Features	External Events
Phonological	1453-Hundred Year's War Ends
Addition of Phonemic Voiced Alveopalatal	1476-Printing Press in England
Fricative and Velar Nasal	1590s-Shakespeare's Works
Great Vowel Shift	1500-1800s-Colonial Activity
Morphological
Inflectional System Similar to Present
Day English
Pronouns Still Inflected
Printing Freezes Many Forms
Syntactic
SVO Syntax Becomes the Norm
Previously Inflected Forms Become
Periphrastic, especially Verbs
Quasi-modals & Noun Adjuncts Become More
Common
Semantic
Borrowed Greek and Latin Scientific Terms     (Ink Horn Terms)
Compounding, Affixation, and Functional Shift

Elaboration: Culturally, England became autonomous; moreover, the advent of printing brought literacy and education, and hence, the affirmation of the London dialect as standard and, eventually, prescriptive grammar.  Most grammatical patterns in place during the EME Period are still in place today.  The most significant internal event during EME is the Great Vowel Shift.  EME may also be seen as the starting point for World Englishes, given the extraordinary colonial activity of the period, including the birth of America.

Internal Changes/Features	External Events
Phonological	Advent of Mass Communication
Relative Stability	Explosion of World Englishes
(especially among consonants)	English becomes Lingua Franca for
Morphological	Science, Air Travel, Information
Inflections Reduced to Eight	International Business, Internet
(2 noun; 4 verb; 2 adjective)
Inflectional Simplification Greater     in Certain Varieties
Syntactic
Periphrastic Elements Become     More Complex
Increase in Quasi-modals & Noun Adjuncts
Semantic
Free Borrowing
Compounding, Affixation, and Functional Shift

Elaboration: Culturally, Standard American English (SAE) has supplanted the London dialect as the desired International version, due in part to mass communication and other modern media.