We have already seen a feature in Outlook 2010 which would automatically check for spelling before sending and email. Similarly Mozilla Thunderbird also provides option which would check for spelling for before sending an email. This can be done using Tools –> Options menu.
Click Tools menu and select Options from the available menu list.
Navigate to Composition tab and then select the Spelling section. Under Spelling section, tick the check box with label as Check spelling before sending. This would automatically check for spelling before sending an email.