Theoretical Grammar The subject-matter of theoretical grammar. Its relation to practical grammar

Growth of sibilants and affricates (see table)
In OE there were no affricates and no sibilants, except [s, z]. the new type of consonants developed from OE palatal plosives [k’, g’], which had split from the corresponding velar plosives [k] and [g], and also from the consonant cluster [sk’]. The three new phonemes which arose from these sources were [t∫], [dз] and [∫]. In Early ME they began to be indicated by special letters and digraphs, which came into use mainly under the influence of the French scribal tradition – ch, tch, g, dg, sh, ssh, sch. As a result of these changes – and also as a result of the vocalization of [γ] – the consonant system in Late ME was in some respects different from the OE system.
phonetic changes in Modern English
XIV – XV

• 
  a: – ei name [namэ ] – name [neim]
  
• 
  i: – ai tide [tidэ ] - tide [taid]
  
• 
  u: - au now [nu:] - now [nau]
  

XV – XVI

• 
  e: - i: deep {de:p] – deep [di:p]
  
• 
  o: – u: doo(n) [do:n] – do {du:]
  
• 
  o,: - ou home [ho:mэ ] – home [houm]
  
• 
  e,: - e: see {sє: ] – see [se:]
  
• 
  ee [i:] - ME e: OE deop [deo:p] – ME deep [de:p] – XVI deep [di:p]
  
• 
  ea [e:] - MEe,: OE daelan [dae:lan] – ME deelen [dє:len] – XVI deal [de:l]
  
• 
  XVII see [si:], sea [se:] – MnE see, sea [si:], ee, ea – [i:]
  
• 
  e:r – i:r – iэ [be:r – bi:r – biэ] beer
  
• 
  o:r – ur – uэ [po:r – pu:r – puэ] poor
  
• 
  e,:r – e:r -єэ [ tє:r – te:r – tєэ] tear
  
• 
  e,:r – e:r – i:r – iэ [klє:r – kle:r – kli:r – kliэ] clear
  
• 
  ir – air – aiэ [fi:r – fair – faiэ] fire
  
• 
  u:r – aur – auэ [our – aur – auэ] our
  
• 
  a:r – eir - єэ [ka:re – keir – kєэ] care
  
• 
  o:r – our – oэ - o: [mo:re – mour – moэ - mo:]
  
• 
  ar – a: [far – fa:] far
  
• 
  or – o: [for – fo:] for
  
• 
  ir - э: fir [fэ:]
  
• 
  er – э: her [hэ:]
  
• 
  ur - э: fur [fэ:]
  

1. [a] – [ae] that [ 0at] – that [0aet]
but: after w or before r [a] – [a] (washen, sharpen)
2. [e] – [a] (before r) sterre – star It’s reflected in spelling.
But: ME herte – MnE hearte [hart] (compromised writing)
But: ME , MnE clerk [kla:rk] (the pronunciation isn’t reflected in spelling)