Your freespeech account can have multiple VOIP lines, each with separate numbers, all billed on the same account.
Ideal for an office or home environment where there's need for a number of phones and the bill is centrally paid. You don't have to have them in the same location, so you could place one it the office and one at home. Calls can easily be transferred from one phone to the other.
Each VOIP line has it's own separate voicemail, phone book, missed call settings and phone numbers.
To get another line check extra VOIP lines, you may also want to add an extra phone number.
If just want to add a phone and don't want a new number, check out the multiple phones feature.