In the annotation edit box, either attached or detached, and in the Text tab, you can let Elan spell check the text. To do so, first make sure the tiers that you want to spell check have its content language set to the same language as the spell checking service (see Changing tier attributes) and then set up a spell checking service.
To set up a spell checking service, go to Edit > Edit Spell Checking Services... (see figure below). In the dialog click Add. Choose the Type and the language for which this spell checking service is set up. Each spell checker type requires its own specific information.
The type Hunspell (see also http://hunspell.github.io/) requires only a path to a dictionary file and its corresponding affix file. Click on Browse and browse to and select a Hunspell dictionary file (with extension .dic, download from https://cgit.freedesktop.org/libreoffice/dictionaries/tree/). Make sure that in the directory of the dictionary the corresponding affix file (with extension .aff) is also there. After selecting the dictionary file click Open. Then click OK.
The type Gecco is a webservice for spell checkers developed at Radboud University Nijmegen. So far, there are two implementations: one for english (see http://fowlt.net/info) and one for dutch (see http://valkuil.net/info). This type requires a URL, a username and a password. After entering those click OK.
The new spell checking service is identified in the dropdown menu by a the language identification, the type and the path to the dictionary and affix file. When selecting a service a more eleborate description is displayed in the text box. Click Close to finish.
In the timeline viewer open an annotation editor, either attached or detached, on a tier that has its content language set to the language of the spell checking service you have set up. On opening and on editing the text will be spell checked. Spell errors are indicated by a red wavy line under the incorrect word (see figure annotation_editor.png).
In the Text tab, when selecting a tier that has its content language set to the language of the spell checking service you have set up, the annotation text is spell checked. Again, spell errors are indicated by a red wavy line under the incorrect word.