All A logical connectives have truth table TTTF.

    TRUE a TRUE = TRUE
    TRUE a FALSE = TRUE
    FALSE a TRUE = TRUE
    FALSE a FALSE = FALSE

So {a}'s truth table is TTTF.

    TRUE a nai TRUE = TRUE
    TRUE a nai FALSE = TRUE
    FALSE a nai TRUE = FALSE
    FALSE a nai FALSE = TRUE

Thus, {a nai}'s truth table is TTFT.

    TRUE na a TRUE = TRUE
    TRUE na a FALSE = FALSE
    FALSE na a TRUE = TRUE
    FALSE na a FALSE = TRUE

And {na a}'s truth table is TFTT.

Logical connection and truth tables http://jbotcan.org/cllc/c14/s1.html

The Four basic vowels http://jbotcan.org/cllc/c14/s2.html

All 16:

TTTT    (always true)
TTTF    first is true and/or second is true.
TTFT    first is true if second is true.
TTFF    first is true whether or not second is true.
TFTT    first is true only if second is true.
TFTF    whether or not first is true, second is true.
TFFT    first is true if and only if second is true.
TFFF    first is true and second is true

FTTT    first and second are not both true.
FTTF    first or second is true, but not both.
FTFT    whether or not first is true, second is false.
FTFF    first is true, but second is false.
FFTT    first is false whether or not second is true.
FFTF    first is false, but second is true.
FFFT    neither first nor second is true.
FFFF    (always false)