ᴱQ. [ð] became [θ] before voiceless stops and [s]; [ð{ptks}] > [θ{ptks}]
Reference ✧ PE12/24
Order ()
| After | voiced stops became spirants after vowels | |||
| Before | [ð] became [z] | 
Phonetic Rule Elements
| 
                   | 
               > | 
                   | 
               ✧ PE12/24 (đ + voiceless stop > þ) | 
| 
                   | 
               > | 
                   | 
               
Phonetic Rule Examples
| kʷoðse > kʷoθse | ðs > θs | ᴱ√QOŘO > ᴱQ. qosse | ✧ QL/78 | 
| neðs > neθs | ðs > θs | ᴱ√NEŘE > ᴱQ. †nes | ✧ QL/66 | 
| reðse > reθse | ðs > θs | ᴱ√reðe > ᴱQ. resse | ✧ QL/79 | 
| veðse > veθse | ðs > θs | ᴱ√VEŘE > ᴱQ. †vesse | ✧ QL/101 | 
| amboðt > amboθt | ðt > θt | ᴱ✶a-mbod-t’ > ᴱQ. ambos | ✧ PE13/139 | 
| boðta > boθta | ðt > θt | ᴱ√BOÐO > ᴱQ. posta | ✧ QL/75 | 
| gʷiðte > gʷiθte | ðt > θt | ᴱ√GWIÐI > ᴱQ. ’wiste | ✧ QL/103 | 
| ɣuðta- > ɣuθta- | ðt > θt | ᴱ√UŘU > ᴱQ. usta- | ✧ QL/98 | 
| ɣʷaðta- > ɣʷaθta- | ðt > θt | ᴱ√ẆAÐA > ᴱQ. wastar | ✧ QL/102 | 
| ɣʷaθto > ɣʷaθto | ðt > θt | ᴱ√ẆAÐA > ᴱQ. wasto | ✧ QL/102 | 
| kʷoðta- > kʷoθta- | ðt > θt | ᴱ√QOŘO > ᴱQ. qosta- | ✧ QL/78 | 
| mbaðto > mbaθto | ðt > θt | ᴱ√NGWAÐA > ᴱQ. masto | ✧ QL/60 | 
| oðto > oθto | ðt > θt | ᴱ√OŘO > ᴱQ. osto | ✧ QL/71 | 
| puðt > puθt | ðt > θt | ᴱ√PUŘU > ᴱQ. pus | ✧ QL/75 | 
| raðta > raθta | ðt > θt | ᴱ√RAŘA > ᴱQ. rasta | ✧ QL/79 | 
| soðta- > soθta- | ðt > θt | ᴱ√SOŘO > ᴱQ. sosta- | ✧ QL/85 | 
| soðto- > soθto- | ðt > θt | ᴱ√SOŘO > ᴱQ. sosto- | ✧ QL/86 | 
| soðto- > soθto- | ðt > θt | ᴱ√SOŘO > ᴱQ. sosto | ✧ QL/86 | 
| teðte > teθte | ðt > θt | ᴱ√TEŘE > ᴱQ. teste | ✧ QL/91 | 
| tuðture > tuθture | ðt > θt | ᴱ√TUŘU > ᴱQ. tusture | ✧ QL/96 | 
| veðta- > veθta- | ðt > θt | ᴱ√VEŘE > ᴱQ. vesta- | ✧ QL/101 | 
| veðta > veθta | ðt > θt | ᴱ√VEŘE > ᴱQ. vesta | ✧ QL/101 | 
| veðtin > veθtin | ðt > θt | ᴱ√VEŘE > ᴱQ. vestin | ✧ QL/101 |