Hello World in Multiple Languages
16 languages, 1363 bytes
 #define ip&quot;MemuL tulaS&quot;,,,,,,,,,,&quot;!&quot;,@++++++++++[&gt;+++++++&gt;++++++++++&gt;+++&gt;+&lt;&lt;&lt;&lt;-]&gt;++.&gt;+.+++++++..+++.&gt;++.&lt;&lt;+++++++++++++++.&gt;.+++.------.--------.&gt;+.@,kc&quot;Kaixo Mundua!&quot;v#!
#define print(A,B,C)main(){printf(&quot;Helo Byd!&quot;);}//ss                                                                          ;ooooooooooooooooooo&quot;Moni Dziko Lapansi!&quot;&lt;[-
#ifdef __cplusplus//p                                                                                                                                 ;;];;
#include&lt;cstdio&gt;//ffffffffff?
#define print(A,B,C)int main(){printf(&quot;Halo Dunya!&quot;);}//ssp
#endif//;  [;;;;;;;;;     &quot;!etejivs vardzoP&quot;]
#ifdef __OBJC__//;;;;;
#define print(A,B,C)main(){printf(&quot;Hallo Welt!&quot;);}//ss
#endif//\
&quot;&quot;&quot;echo&quot; &quot;Salom Dunyo!&quot;;&quot;exit&quot;;puts&quot;Moien Welt!&quot;;\
__END__
#define B//\
&quot;&quot;&quot;#;;;;;
print([&quot;Hai dunia!&quot;,&quot;Hej Verden!&quot;,&quot;Halo Dunia!&quot;][(int(1&gt;0)is 1)+~int(-1/2)*2])
#define s eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeejeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeejiiiiiiiijeeeeeeeeeeeeeejiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiijeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeejeejijiiiiiiiiiijeeeeeeeeeeejiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiij
#define U   !&quot;!dlereW ollaH&quot;&lt;           ;
#define T@,kc&quot;Sannu Duniya!?%?&quot;

Try it online!
(use &quot;switch languages&quot; to change language)

Python 3 = Halo Dunia! (Indonesian)

Python 2 = Hej Verden! (Danish)

Python 1 = Hai dunia! (Malay)

C (gcc) = Helo Byd! (Welsh)

C++ (gcc) = Halo Dunya! (Sundanese)

Objective C (clang) = Hallo Welt! (German)

Brainfuck = Hello World! (English, obviously)

Befunge-93 = Salut Lume! (Romanian)

Ruby = Moien Welt! (Luxemburgish)

Bash = Salom Dunyo! (Uzbek)

Befunge-98 (PyFunge) = Kaixo Mundua! (Basque)

Unefunge-98 (PyFunge) = Sannu Duniya! (Hausa)

Cardinal = Hallo Wereld! (Dutch)

Alphuck = Ciao mondo! (Italian)

&gt;&lt;&gt; = Moni Dziko Lapansi! (Chichewa)

Fission = Pozdrav svijete! (Croatian)


Any golfing tips are welcome (especially on the Brainfuck)!!
Thanks to @JonathanFrech for -1 byte! Also, thanks to @ovs for -40 bytes!
How (general ideas, I actually forgot specifics)??
The languages can be put into four groups:

Macro: C, C++, Objective C
Comment: Python3, Python2, Python1, Ruby, Bash
Dimensional: Befunge-93, Befunge-98, Unefunge-98, Cardinal, &gt;&lt;&gt;, Fission
Vulgar: Brainfuck, Alphuck

The Macro languages see # as the start of a preprocessor directive. These are used for three reasons: to house code for other groups, to distinguish among Macro languages, and to actually define a macro. All three use // as comment, so after that we store code for the other groups. Also, the backslash continues the comment in these languages.
The Comment languages see # as the start of a comment. The quirk here is the triple quotes, which distinguish the Pythons from Ruby from Bash. And to distinguish Python 1 from 2 from 3, we use a distinguishing feature in all three, along with an array of outputs. Oh yeah, there's also that __END__. This is used to end the code for some (can't remember exactly which ones) of the Comment languages.
The Dimensional languages are distinguished in a way that is hard to explain. One has to know the specifics of each language to figure it out. For example, # is only a skip in the fungeoids, while it does various different things in the other languages. The code is strewn about everywhere for these languages.
And finally, we arrive at the Vulgar languages. These two ignore everything that isn't in their set of valid characters. A balancing act has to be played with these languages and the others, as the code already contains characters in the character sets.
Edit: Wow... Somehow I only now realized Brainfuck did not seem to work, so that's fun!