One of the many unique features about Horde webmail is it’s spell checker facility. However, the use of this requires that certain components be installed. To install these follow these instructions:
1) Login to your Linux box via SSH as root.
2) Install aspell by running the following command:
yum -y install aspell aspell-en-gb
Leave it to install; you shouldn’t need to make any changes to Horde as it should automatically detect the ASPELL installation.