Feel free to read the provided lines here, or from episode five's script (deep/dark voice), or from episode six's script.

Tabitha is the original ghost in the Hamilton House. Her family built it years before she was born. One day she was playing in the yard when she noticed a well. She got to close and fell in.
She didn't die right away. She cried for help. Little Tabitha was only six. She was scared and alone. When she died (in the 1850s) she was so lonely that she found a way to use the house as a beacon to draw in other lost and lonely spirits to keep her company.

*Note: This character is in very few episodes in season one, but the voice actor may be used for other characters.*