AMPscript issue with IF AND

Question

Here is my script:

%%[IF[Language] == "FR"  AND [Gender] == "F" THEN]%%
    Chère 
%%[ELSE]%%
    Cher 
%%[ELSEIF[Language] == "NL"  THEN]%%
    Beste 
%%[ELSE]%%
    Beste 
%%[ENDIF]%% 

%%FirstName%% %%LastName%%,
%%=UpperCase([Language])=%%, 
%%=LowerCase([Gender])=%%
%%=UpperCase([EmailAddress])=%%

In Belgium we're bilingual French and Dutch and need to display the salutations accordingly.

Answer 1

From your code, it seems like you are only checking for French gender, and the same salutation is used for Dutch. In that case you could try this:

    %%[

        IF([Language] == "FR"  AND [Gender] == "F") THEN]%%Chère 


%%[ELSEIF ([Language] == "FR" AND [Gender] != "F") THEN]%%Cher 
    %%[ELSEIF ([Language] == "NL"  [Gender] == "F") THEN]%%Beste
    %%[ENDIF]%% 
    %%FirstName%% %%LastName%%,
    %%=UpperCase([Language])=%%, 
    %%=LowerCase([Gender])=%%
    %%=UpperCase([EmailAddress])=%%

OR

    %%[IF([Language] == "FR"  AND [Gender] == "F") THEN]%%Chère 
    %%[ELSEIF ([Language] == "FR" AND [Gender] != "F") THEN]%%Cher 
    %%[ELSE]%%Beste
    %%[ENDIF]%% 
    %%FirstName%% %%LastName%%,
    %%=UpperCase([Language])=%%, 
    %%=LowerCase([Gender])=%%
    %%=UpperCase([EmailAddress])=%%

Answer 2

@Data_Kid's answer is correct. I don't speak Dutch, but there's potentially a nuance with French with whether you know the gender, but do not know the customer's first name. This may not be useful if your FirstName field is always populated...

<!--
%%[
    VAR @salutation, @firstname

    IF EMPTY(Language) THEN
        SET @salutation = 'Beste'
    ELSEIF Language == 'FR' AND Gender == "F" THEN
        SET @salutation = 'Chère'
    ELSEIF Language == 'FR' THEN
        SET @salutation = 'Cher'
    ELSE
        SET @salutation = 'Beste'
    ENDIF

    IF EMPTY(FirstName) THEN
        IF Language == "FR" AND Gender == "F" THEN
            SET @firstname = 'Cliente'
        ELSEIF @language == 'FR' THEN
            SET @firstname = 'Client'
        ELSE
            SET @firstname = 'Klant'
        ENDIF
    ELSE
        SET @firstname = FirstName
    ENDIF
]%%
-->
%%=v(@salutation)=%% %%=v(@firstname)=%%,