public class SpellCheckerDictionaryCollection :
    Collection<object>

Public Class SpellCheckerDictionaryCollection
    Inherits Collection(Of Object)

<!--Add the following namespace declarations: 
xmlns:dxre="http://schemas.devexpress.com/winfx/2008/xaml/richedit"
xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
xmlns:dxspch="http://schemas.devexpress.com/winfx/2008/xaml/spellchecker"-->

<dxre:RichEditControl CommandBarStyle="Ribbon"
                      x:Name="richEditControl" 
                      DocumentSource="An ideal dictionarie shouldbe comprised of all the the words in a given langauge">
<dxre:RichEditControl.SpellCheckerOptions>
<dxre:DXRichEditSpellCheckerOptions AutoDetectDocumentCulture="False"/>
</dxre:RichEditControl.SpellCheckerOptions>
    <dxmvvm:Interaction.Behaviors>
        <dxspch:RichEditSpellChecker CheckAsYouType="True"
                                     Culture="en-US"
                                     IgnoreMixedCaseWords="False"
                                     IgnoreUri="False"
                                     SpellingFormType="Word">
            <dxspch:RichEditSpellChecker.Dictionaries>
                <dxspch:HunspellDictionary Culture="en-US" 
                                           DictionaryUri="pack://application:,,,/Dictionaries/en_US.dic"
                                           GrammarUri="pack://application:,,,/Dictionaries/en_US.aff"/>
                <dxspch:SpellCheckerCustomDictionary Culture="en-US"
                                                     DictionaryUri="Dictionaries/CustomEnglish.dic"
                                                     AlphabetUri="Dictionaries/EnglishAlphabet.txt"/>
            </dxspch:RichEditSpellChecker.Dictionaries>
        </dxspch:RichEditSpellChecker>
    </dxmvvm:Interaction.Behaviors>
</dxre:RichEditControl>