```python
from langchain.prompts.chat import ChatPromptTemplate

template = "You are a helpful assistant that translates {input_language} to {output_language}."
human_template = "{text}"

chat_prompt = ChatPromptTemplate.from_messages([
    ("system", template),
    ("human", human_template),
])

chat_prompt.format_messages(input_language="English", output_language="French", text="I love programming.")
```

```pycon
[
    SystemMessage(content="You are a helpful assistant that translates English to French.", additional_kwargs={}),
    HumanMessage(content="I love programming.")
]
```