From Teflpedia

The sequence "io" normally is part of two syllables (as in "sociology") or the "i" modifies the sound of the previous letter as in "action". This page sets out some words teachers can use to help their students become more aware of how they can sound out more correctly the different sounds corresponding to words containing "io".

Modified "c", "s", "t" + "io"[edit | edit source]

See also: Decoding exercises: "sion", Decoding exercises: "tion"

The letters "c", "s" and "t" often change their sound when followed by an "i".

  • "cio" as /ʃə/: suspicion
  • "cio" as /ʃə/ or /ʒə/AmE: coercion
  • "sio"
  • as /ʒə/: conclusion, confusion, decision, division, explosion, occasion, occasional, precision, provision, television, vision, visionary
  • as /ʃə/: compulsion, extension, pension, propulsion, revulsion, tension, torsion
  • "ssio" as /ʃə/: admission, aggression, compassion, compassionate, confession, depression, discussion, mission, missionary, profession
  • "tio"
  • as /ʃə/: action, addition, additional, condition, education, function, functional, information, nation, organization, position, relation, situation, tradition, traditional
  • as /ʃə/ or /ʃ/: national
  • as /tʃə/: question, suggestion
  • as /ʃə/ or /tʃə/: attention, intention, mention
  • as /ʒə/: equation
  • as /ʃiːəʊ/: ratio

Unmodified "c", "s", "t" + "io"[edit | edit source]

  • "cio" as /siːəʊ/: nuncio, sociocultural
  • "cio" as /siːɒ/: sociology
  • "cio" as /siːə/: sociological
  • "sio" as /ziːəʊ/: physiotherapy
  • "sio" as /ziːɒ/: anaesthesiology,BrE anesthesiology,AmE physiology
  • "tio" as /tiːə/: bastion

Two syllables[edit | edit source]

  • /aɪɒ/: biology
  • /aɪɒ,BrE aɪɔːAmE/: priority
  • /aɪəʊ/: Ohio
  • /aɪə/: Iowa, lion, prior, violence
  • /iːəʊ/: cardio, cardiovascular, Ethiopia, studio
  • /iːɒ/: cardiology
  • /iːə/: champion, criterion, interior, period, radio, senior, union

One syllable[edit | edit source]

  • /jə/: behavior,AmE behaviour,BrE billion, onion, opinion
  • /ə/: region, religion, fashion

Variant pronunciations[edit | edit source]

  • /ʃiːɒ, siːɒ/: glaciology

"ious"[edit | edit source]

  • "ious" as /iːəs/: curious, obvious, previous, serious, various
  • "ious" as /əs/: anxious, religious
  • "cious" as /ʃəs/: atrocious, audacious, auspicious, conscious, delicious, malicious, precious, suspicious

References[edit | edit source]