Nokia 1508i User Manual page 23

To get a list of special characters, when using predictive
text input, press and hold *; if there is no active word,
press *.
If the displayed word is the one you want, press 0, and
start writing the next word. To change the word, press *
repeatedly until the word you want appears. If ? is
displayed after the word, the word is not in the dictionary.
To add the word to the dictionary, select Spell, enter the
word (using traditional text input), and select Save.
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