The function appears to take a string input, swap adjacent characters in pairs starting from the first character, and then increment the last character by one.

[CODE]:
```python
def approximate_function(input_string):
    output_string = ""
    for i in range(0, len(input_string) - 1, 2):
        output_string += input_string[i + 1]
        output_string += input_string[i]
    if len(input_string) % 2 == 1:
        output_string += chr(ord(input_string[-1]) + 1)
    else:
        output_string = output_string[:-1] + chr(ord(input_string[-1]) + 1)
    return output_string
```

To further confirm the function behavior, we can test more cases:

COMMAND: PYTHON(./temp/function.py "sample" "testing" "more" "inputs" "Computational" "Linguistics")