tavla -tav-ta'a- gismu

x1 talks/speaks to x2 about subject x3 in language x4.

Not limited to vocal speech, but this is implied by the x4 without context of some other medium of conversation (use cusku, casnu, skicu, ciksi for weaker implication of vocal communication); converse/discuss/chat (= simta'a, simsku, vricysimta'a for a conversation not clearly delimited by subject). See also bacru, cusku for actual expression, casnu, darlu, skicu, ciksi, bangu.

In notes:

bacru
x1 utters verbally/says/phonates/speaks [vocally makes sound] x2.
bangu
x1 is a/the language/dialect used by x2 to express/communicate x3 (si'o/du'u, not quote).
casnu
x1(s) (mass normally, but 1 individual/jo'u possible) discuss(es)/talk(s) about topic/subject x2.
ciksi
x1 (person) explains x2 (event/state/property) to x3 with explanation x4 (du'u).
cusku
x1 (agent) expresses/says x2 (sedu'u/text/lu'e concept) for audience x3 via expressive medium x4.
darlu
x1 argues for stand x2 against stand x3; [an opponent is not necessary].
skicu
x1 tells about/describes x2 (object/event/state) to audience x3 with description x4 (property).
ba'usku
x1 (agent) says x2 (sedu'u/text/lu'e concept) for audience x3 through expressive medium x4.
ba'usle
s1 (phone/speech sounds) is a segment of utterance/speech stream s2=b2.
ctununta'a
n1=c5 is a lecture / an event of verbal teaching by t1=c1 to audience t2 = c2 about subject t3 = c4 in language t4 with facts taught c3.
da'arta'a
t1=d1 quarrels with t2=d2 about issue t3=d3 in language t4.
filta'a
t1=f2 speaks fluently to t2 about subject t3 in language t4 under conditions f3.
nalta'acni
c1=t1 is withdrawn, feeling emotion c2 about c3=t3 from t2.
nunflapai
n1 is a trial of dispute j2 involving people f3.
sagjvetavdraci
d1=s2=t3 is a musical/operetta about d2 composed/written by d3 for audience d4=s3=t2 with actors d5=s1=t1.
samta'a
t1 talks via computer to t2 about t3 in language t4.
ta'arsi'u
s1 (set) discuss subject t2 in language t4.
terlisri
l3 tells/narrates about subject l2 with narration l1 to audience l4.