Adding text to a bound TextBlock

If you want to do it in the binding:

<TextBlock Foreground="#FFC8AB14" FontSize="28">
    <TextBlock.Text>
        <Binding Path="Title">
            <Binding.StringFormat>
                This is "{0}"
            </Binding.StringFormat>
        </Binding>
    </TextBlock.Text>
</TextBlock>

Element syntax required to escape quotes. If the quotes where just to mark the inserted text and should not appear in the output it is much easier of course:

<TextBlock Text="{Binding Title, StringFormat={}This is {0}}" Foreground="#FFC8AB14" FontSize="28">

You could do this with a converter.

<TextBlock Text="{Binding Title, ConverterParameter=This is, Converter={StaticResource TextPrefixConverter}}" Foreground="#FFC8AB14" FontSize="28" />

The converter would simply prefix the bound value with the ConverterParameter.

public class TextPrefixConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {                        
        String result = String.Empty;
        if ( parameter != null)
            result = parameter.ToString( );

        if (value != null)
            result += value.ToString( );

        return result;
    }
...
}

It's not obvious is the spaces and/or quotes are intended to be part of the output. If so, the converter could be changed to trim the spaces and/or add quotes to the constructed string.

Another way of doing this is:

<TextBlock Foreground="#FFC8AB14" FontSize="28" >
    <Run Text="This is " />
    <Run Text="{Binding Path=Title}" />       
</TextBlock>

You can use the StringFormat property of the binding:

 <TextBlock Text="{Binding Title, StringFormat=This is {0}}"></TextBlock> 

Check out this blog post for more information: WPF String.Format in XAML with the StringFormat attribute.