What potential diagnosis would explain the following symptoms in a 65-year-old married female with 16 years of education and full-time work as an elementary school teacher? Her symptoms began suddenly one evening; her husband noted she referred to the dog food as 'Jell-O' and called the television remote a 'fork'. She appears to understand conversational language and can read and write normally but is unaware of her paraphasic errors in speech.
