Starbucks to English
Javascript ES6, 902 900 bytes
s=>(R=(l,r)=>(l.split`.`.map((e,i,l)=>!(i%2)&&(r=r.split(e).join(l[i+1]+" "))),r),R("-.no.!.-tuple.1/2.half-caf.1/3.one-third-caf.2/3.two-thirds-caf.ECP.Econ panna.CM.RY.CR.RZ.EM.EY.WC.whip.Wh.whole-milk.A.americano.B.breve.C.cappuccino.D.extra.E.espresso.F.foam.G.grande.H.hazelnut.I.venti.L.latte.M.OZ.N.skim.O.mocha.R.caramel.S.short.T.tall.V.vanilla.X.decaf.Y.macchiato.Z.drizzle.%.two-percent",R(",1,,,,E.solo.,2,,,,E.doppio",s).split`,`.map((e,i)=>(`1VI.2MO.2CR.4xD`.split`.`.map(k=>k[0]==i&&(e=e.split(k[1]).join(k[2]))),i==1?(e=R("1!.single.2!.double.3!.triple.4!.quadruple.5!.quintuple",e.replace(/(\d+)/,"$1!"))):i==2?(e=R("10.ten.20.twenty.11.eleven.12.twelve.13.thir0.14.four0.15.fif0.16.six0.17.seven0.18.eigh0.19.nine0.0.teen.1.one.2.two.3.three.4.four.5.five.6.six.7.seven.8.eight.9.nine",e)):s.includes`E`&&(e=R("single.solo.double.doppio",e)),e)).join` `).replace(/\s+/g," ").trim())
"Ungolfed":
s=>(
R=(l,r)=>(l.split`.`.map((e,i,l)=>!(i%2)&&(r=r.split(e).join(l[i+1]+" "))),r), // consecutive string replacement function
R("-.no.!.-tuple.1/2.half-caf.1/3.one-third-caf.2/3.two-thirds-caf.ECP.Econ panna.CM.RY.CR.RZ.EM.EY.WC.whip. // replace all symbols with appropriate values
Wh.whole-milk.A.americano.B.breve.C.cappuccino.D.extra.E.espresso.F.foam.G.grande.H.hazelnut.I.venti.L.latte.
M.OZ.N.skim.O.mocha.R.caramel.S.short.T.tall.V.vanilla.X.decaf.Y.macchiato.Z.drizzle.%.two-percent",
R(",1,,,,E.solo.,2,,,,E.doppio",s) // if special espresso cases, directly replace entire string
.split`,`.map((e,i)=>( // split input at commas
`1VI.2MO.2CR.4xD`.split`.`.map(k=>k[0]==i&&(e=e.split(k[1]).join(k[2]))), // substitute duplicate symbols with unique symbols
i==1?(e=R("1!.single.2!.double.3!.triple.4!.quadruple.5!.quintuple",e.replace(/(\d+)/,"$1!"))): // if in shots section, expand all numbers
i==2?(e=R("10.ten.20.twenty.11.eleven.12.twelve.13.thir0.14.four0.15.fif0.16.six0.17.seven0.18.eigh0. // if in syrup section, expand all numbers
19.nine0.0.teen.1.one.2.two.3.three.4.four.5.five.6.six.7.seven.8.eight.9.nine",e)):
s.includes`E`&&(e=R("single.solo.double.doppio",e)), // replace single,double with solo,doppio if espresso is in the string
e)).join` `).replace(/\s+/g," ").trim()) // join sections, cleanup whitespaces
Example runs:
f(",3G,V,Wh,,L") -> triple grande vanilla whole-milk latte
f("X,2T,,N,,L") -> decaf double tall skim latte
f("1/2,V,,,,CM") -> half-caf venti caramel macchiato
f("2/3,3V,3V,B,WC,L") -> two-thirds-caf triple venti three vanilla breve whip latte
f(",G,,,xCR,CM") -> grande extra caramel drizzle caramel macchiato
f("X,4T,2M 2C,B,xWC -F xM,C") -> decaf quadruple tall two mocha two caramel breve extra whip no foam extra mocha drizzle cappuccino
f(",2,1V,B,,EM") -> doppio one vanilla breve espresso macchiato
f(",1,,,,E") -> solo
f(",2,,,,E") -> doppio
f(",3,,,,E") -> triple espresso
Python, 824 815 807 805 bytes
f=lambda s,a=0:a==0and" ".join(" ".join(f(" "+s.split(",")[i],(["X,deC,1/2,half-C,1/3,oneT-C,2/3,twoTs-C,C,caf,T,-third","".join(" %i"%i+f(",%i-tupL,"%i,["1","x","2","y"])for i in range(6,21))+"1,solo,2,doppio,"*('E'in s)+"1,singL,2,doubL, 3,tripL, 4,quadrupL, 5,quintupL,x,1,y,2,S,short,T,tall,G,grande,V,Vnti","V, vanilla,H, hazelnut,10,ten,11,eleVn,12,twelV,13,thirT,14,4T,15,fifT,16,6T,17,7T,18,8een,19,9T,20,twenty,1,one,2,two,3,three,4,four,5,fiV,6,six,7,seVn,8,eight,9,nine,T,teen","Wh,whole-milk,%,two-percent,N,skim,B,breV","x,extra ,-,no ,F,foam,WC,whip,M,MR,R, drizzL","CM,xM,E,espresso,M, macchiato,CP, con panna,A,americano,L,latte,C,cappuccino,x,C"][i]+",C, caramel,M, mocha,L,le ,V,ve").split(","))for i in range(6-(s in",1,,,,E,2,,,,E"))).split())or a and f(s.replace(a[0],a[1]),a[2:])or s
Slightly more readable:
def f(s,a=0):
if a==0:
a=["X,deC,1/2,half-C,1/3,oneT-C,2/3,twoTs-C,C,caf,T,-third"]
a+=["".join(" %i"%i+f(",%i-tupL,"%i,["1","x","2","y"])for i in range(6,21))+"1,solo,2,doppio,"*('E'in s)+"1,singL,2,doubL, 3,tripL, 4,quadrupL, 5,quintupL,x,1,y,2,S,short,T,tall,G,grande,V,Vnti"]
a+=["V, vanilla,H, hazelnut,10,ten,11,eleVn,12,twelV,13,thirT,14,4T,15,fifT,16,6T,17,7T,18,8een,19,9T,20,twenty,1,one,2,two,3,three,4,four,5,fiV,6,six,7,seVn,8,eight,9,nine,T,teen"]
a+=["Wh,whole-milk,%,two-percent,N,skim,B,breV"]
a+=["x,extra ,-,no ,F,foam,WC,whip,M,MR,R, drizzL"]
a+=["CM,xM,E,espresso,M, macchiato,CP, con panna,A,americano,L,latte,C,cappuccino,x,C"]
return" ".join(" ".join(f(" "+s.split(",")[i],(a[i]+",C, caramel,M, mocha,L,le ,V,ve").split(","))for i in range(6-(s in",1,,,,E,2,,,,E"))).split())
elif a:
return f(s.replace(a[0],a[1]),a[2:])
else:
return s
Demo at https://repl.it/C8Hz/3
Ruby -plaF,, 975 870 bytes
I got a random upvote on my old, almost-four-year-old answer to this question, and because of my comments on how horribly it went (you can check the post history if you want to see what I wrote before) I was inspired to make it better (aka: rewrite most of it from the ground up) and managed to golf over a hundred bytes off it. Still longer than the Python answer, but I'm much happier with how things turned out now.
About 20 bytes were saved by switching from trying to run regex patterns to affect specific parts of the comma structure to using the -aF, flag to autosplit a line of input on commas and save it to $F, allowing me to modify some elements before stitching it back together and finally modifying the output variable with the last few sub/gsub commands.
Honestly, the number of regex replacements made here means most of this could be a Retina program, but I don't know Retina well enough for that.
g=->n,c{n.grep(/^ ?#{c}/i)[0]}
n=%w"0 one two three four five six seven eight nine ten eleven twelve thir four fif";n+=n[6,4]<<'twenty'
$F[1].sub!(/(\d*)(\w)?/){i=eval$1;"#{i&&(%w"0 sing doub trip quadrup quintup"[i]||$1+"-tup")+"le"} #{g[%w"short tall grande venti",$2]if$2}"}
$F[2].gsub!(/(\d*)(\w)/){i=eval$1;"#{i&&n[i]}#{'teen'if(13..19)===i} #{g[%w"vanilla caramel mocha hazelnut",$2]}"}
$F[3].sub!(/.+/){%w"skim whole-milk breve two-percent"[$&.sum%26%4]}
$F[4].gsub!(/(x|-)?(\w+)/){"#{%w"extra no"[$1.ord%2]if$1} #{g[%w"caramelD mochaD whip foam",$2[0]].sub ?D,' drizzle'}"}
$_=$F*' '
sub(/^\S+/){%w"de - half- one-third- two-thirds-"[$&.sum%8]+"caf"}
sub'CP',' con pana'
sub'CM','caramel'+m=' macchiato'
e='espresso'
gsub(/[A-Z]/){g[%w"americano latte cappuccino"+[m,e],$&]}
gsub(/ +/,' ')
$_.strip!
sub(/[sd]...le/){g[%w"doppio solo",$&[0]]}if$_[e]
sub'o '+e,?o
Try it online!