RP

Lower case a + lower case upsilon

Back, closing and wide.

The glide of RP /aʊ/ begins at a point between the back and front open positions, slightly more fronted than the position for RP /ɑ:/, and moves in the direction of RP /ʊ/ approaching the half-close level [ö]. The glide is much more extensive than that used for /əʊ/ and is symmetrically opposed to the front RP diphthong /aɪ/. The lips change from neutrally open to weakly rounded. English /aʊ/ is similar to the Spanish diphthong in pausa (Span 'pause'), but the end-point is more relaxed and the starting point is a more retracted in Spanish.

Spelling
<ou, ow> loud /laʊd/, frown /fraʊn/ , bow /baʊ/
<ought> drought /draʊt/ , slough /slaʊ/
Rare case:
<eo> MacLeod /məˈklaʊd/
Examples
how /haʊ/
allows /əˈlaʊz/
a louse /ə laʊs/
drought /draʊt/
mountain /ˈmaʊntɪn/
pronounce /prəˈnaʊns/
renown /rɪˈnaʊn/
round-eyed /raʊnd aɪd/
'Turn the brown couch upside-down without doubts', shouted Paul as loudly as he could.

/ ˈtɜ:n ðə ˈbraʊn ˈkaʊtʃ ˈʌpsaɪd daʊn wɪðˈaʊt dˈaʊts | ˈʃaʊtɪd ˈpɔ:l əz ˈlaʊdli əz hi ˈkʊd/

The doughty clown raised his eye-brows when he was allowed to take the plough by the bough, and then browsed his foul task.

/ðə ˈdaʊti ˈklaʊn ˈreɪzd ɪz ˈaɪ braʊz wen ˈhi wəz əˈlaʊd tə ˈteɪk ðə ˈplaʊ baɪ ðə ˈbaʊ | ənd ðen ˈbraʊzd ɪz ˈfaʊl ˈtɑ:sk/

How much ground would a groundhog hog, if a groundhog could hog ground?

/ˈhaʊ ˈmʌtʃ ɡraʊnd wʊd ə ˈɡraʊndˌhɑ:ɡ hɒɡ | ɪf ə ˈɡraʊndˌhɑ:ɡ kəd hɒɡ ɡraʊnd/

Pronunciation

The tongue moves upwards from an open front position to a half-close back position. The lips change from neutraly open to a weakly rounded position. The soft palate is raised (unless followed by a nasal).

PSp

aw

Lower case a + lower case w

Falling diphthong

The first sound in this diphthong is a vowel and the second element is a semivowel. The articulators move from an open position to a close position. To pronounce the second element, the semivowel [w], the tongue is close to the palate, in the same way as when we pronounce /u/. The vocal folds vibrate during the production of this sound.

Spelling
<au>
Examples
autor
causa
sauna
Era de la autoría del caudaloso auditor.
Pronunciation

The first sound is a vowel and the second element is a semivowel. The articulators move from an open position to a close position. The vocal folds vibrate during the production of this sound.