The letter Þ is known as “þorn” (thorn). It makes the same sound as the English thick” or thunder”.[a]
  • þannig, þú, þáttur, þrír

Softer sound in common words

Common words that start with Þ have a tendency to be pronounced much softer, making the Þ letter sound like like Ð, H, or even disappearing completely. See the article Disappearing sounds § Þorn for a further explanation.
This only happens to common words such as það, þetta, þeir, þarna, and only when they are not stressed.
  • Þ will occasionally sound like a Ð:
    • Er það gott? [er ða gott]
  • Þ will occasionally sound like an H:
    • Er það þessi? [er ða hessi]
    • Þetta er flott. [hett er flott]
  • Þ will occasionally completely disappear:
    • Hvað er þetta? [kva er etta]

The letter Þ is unrelated to the letter P, instead it comes from an old runic letter. Þ is not used in languages other than Icelandic today.
Remember that this letter is transcribed as “th” in situations where you don’t have access to an Icelandic keyboard or if you’re using English-only letters for a URL. The word “þangað” is transcribed as “thangad” and not as “pangad”. Icelanders are able to fully understand you if you write “th” because they are used to it.