The true statements are:

phi$1$ OR phi$2$ is satisfiable

Here's why:

Satisfiable Formula: A satisfiable formula is true under at least one interpretation of its variables.

Implications of phi$1$ and phi$2$ being satisfiable:

phi$1$ OR phi$2$ must be satisfiable: If phi$1$ is true for a particular interpretation, then phi$1$ OR phi$2$ is also true for that interpretation, regardless of phi$2\text{'}$s truth value. Similarly, if phi$2$ is true, phi$1$ OR phi$2$ is true. Therefore, at least one of the possible interpretations will make phi$1$ OR phi$2$ true, making it satisfiable.

Other statements are not necessarily true:

NOT phi$1$ is not necessarily unsatisfiable: It could also be satisfiable. If phi$1$ is true for some interpretations, then NOT phi$1$ is false for those interpretations, but it could be true for other interpretations where phi$1$ is false.

NOT phi$2$ is not necessarily valid: It could be valid or satisfiable, depending on the specific formula phi$2.$

phi$1$ AND phi$2$ is not necessarily satisfiable: It's only satisfiable if there exists an interpretation where both phi$1$ and phi$2$ are true simultaneously. This might not always be the case, even if both formulas are individually satisfiable.

Therefore, the only statement that is always true given the satisfiability of phi$1$ and phi$2$ is:

phi$1$ OR phi$2$ is satisfiable