I was walking in the forest...

[Prinsessa]

Vanga:

Hjœyḷųwwœn, vaha fy̨ssæ joyhltnalji hóhha.
[ˈçœ͡ʏl̥ʊ̃wːœn ˈvahɑ ˈfỹɕæ ˈjɔ͡ʏɬtn̥ɑljɯ ˈhɔɧːɑ]

Extremely detailed:

"In which reached I be, its which turns of mine was fallen on me belongs to which reaches."
PLUR-break/reach<PAST><CONTR>-REL.ANIM-LOC-ESS.1PS 3PS-GEN turn-REL.INANIM-POSS.1PS dwell-LOC-CAUS<PAST><CONTR>.3PS-OBJ.1PS break/reach<CONTR>-GEN

More sensible:

"In the forest I was, when my head was befallen me by a tree branch."
PLUR/COLL-tree<PAST>-LOC-ESS.1PS when head.ABS-POSS.1PS fall<PAST>.3PS-OBJ.1PS tree-GEN

[thetha]

Vietnamese
Anh đã đi bộ ở rừng thì cành cây ngã xuống đầu.
MASC.INFORM PST walk LOC forest TOP branch tree fall down head
I was walking in the forest, when a branch fell on my head.

[Pirka]

Я шел по лесу, когда мне на голову упала ветка.
1PSG go.IMPERF-PT.MASC through forest.MASC-LOC when 1PSG-DAT onto head.FEM-ACC fall.PERF-PT-FEM branch.FEM
I was walking in the forest, when a branch fell on my head.

[Prinsessa]

Can be said in lots of ways in Swedish. I'll try some.
Swedish makes no difference between perfective and imperfective past.

Jag gick i skogen, när med ens en gren föll i huvudet mitt.
"I walked in the forest, when of a sudden a branch fell into the head mine."
1PS.NOM walk.PAST in.STAT/DYN forest-DEF.NOM.SING.C when with at_all/once INDEF.NOM.SING.C branch.NOM fall.PAST in.STAT/DYN head-DEF.NOM.SING.N POSS.1PS.SING.N

I skogen traskade jag, då en trädgren så datt i min skalle.
"In the forest walked I, then a treebranch so fell in my skull."
in.STAT/DYN forest-DEF.NOM.SING.C walk-PAST 1PS.NOM then INDEF.NOM.SING.C tree.NOM-branch.NOM so fall.PAST in.STAT/DYN POSS.1PS.SING.C skull.NOM

Å färde var jag i genom skogen och så trillade utan förvarning en diger kvist upp å hjässan min.
"On journey was I through the forest and so fell without forewarning a large twig upon the top of head mine."
on journey-DAT be.PAST 1PS.NOM in through forest-DEF.NOM.SING.C and so fall-PAST without fore-warning.NOM INDEF.NOM.SING.C big.NOM twig.NOM up on top_of_head-DEF.NOM.SING.C POSS.1PS.SING.C

Under en skogstur fick jag rätt ur det blåa en gren i knoppen.
"During a foresttrip got I right out of the blue a branch in the bud."
SUBESS/SUBLAT INDEF.NOM.SING.C forest-GEN-trip.NOM get.PAST 1PS.NOM right.N out.DYN DEF.NOM.SING.N blue-DEF.SING.N INDEF.NOM.SING.C branch.NOM in.STAT/DYN bud-DEF.NOM.SING.C

Note how the possessive pronoun disappears in the last one. We generally don't use them in such cases, like where, in this example, I said 'I got […] in (my) head', because by saying who got it there, it's unnecessary to specify whose head it was. We already know.

Now, I had some fun with the words above. I'd expect to hear something like this out of most, boring people:

Alltså... Jag liksom gick i skogen, bara, och så bara plötsligt får jag värsta greeeeeenen i skallen!!!!!!!
Like... I, like, walked in the forest (<- how can you be uncertain of something like that?), like, and so like suddenly get (<- SUDDEN TENSE SHIFT :pPPP) I the worst (<- what?!) braaaaaanch in the skull!!!!!!!

I'm not going to gloss that.

[Toko]

sdov kho utje gyzh yluvj kushj tovysay nje hjeshj tje ylje

forest in already walk while fall branch (subject marker) head personal into

While I walked through the forest, a branch fell on my head.

Notes:
tje - lit. "personal", but also marks possession (bu - you, bu tje / butje* - your) and somewhat more modernly is a neuter first person singular pronoun
- utje is what sets this in the past, however if this was some sort of narrative story it would probably be told in the present like most other Zelsen folk tales (only thought of this because of the Zelsen rhyme "Gyzh zhos nje sdov ila / ta zhje zho nje ch' sva / yk zhot nje hjesh' tovysay." "A man walks through the forest / And he ponders many things / He hits his head on a tree branch")
* - bu and tje are considered seperate words even when used in conjunction like this, but some may prefer to combine them in romanization to duplicate the "attachment" of the Mayk symbol "tje" to the Myk alphasyllabic characters that is seen in Zelsen writing.

[Chagen]

Adari: Two ways to say this:

Arrigorzu fentegi, Çûth reptcu yg rêć viglaati.
[forest-ACC walk-IMPER.PST-1.SG, branch head-ACC 1.SG-GEN when in-fall-PST-1. SG]
"I was walking in the forest, when a branch fell on my head."

"Arrigozu y fentir, Çûth reptcu yg rêć viglaati."
[forest-ACC 1.SG.NOM walk-PARTICPLE.DUR, branch head-ACC 1.SG-GEN when in-fall-PST-1.SG]
"While I walked/was walking in the forest, a branch fell on my head."

[prettydragoon]

Rireinutire:
Ma remera opakiva ita puke mano peare susukiva.
ma-0 reme-ra opa-ki-va ita puke-0 ma-no pea-re susu-ki-va
1S-NOM forest-INE walk-PST-SENS and.then branch-NOM 1S-GEN head-ILL fall-PST-SENS
I was walking in the forest and then a branch fell on my head.

[xinda]

I was walking in the forest when a branch fell on my head.

:roc: 我在森林裡散步的時候突然有個樹枝掉到我頭上。
wǒ zài sēnlín li sànbù de shíhou túrán yǒu gè shùzhī diào dào wǒ tóushàng
1s LOC forest in stroll GEN time suddenly be COUNTER branch fall to 1s head up

森の中で散歩している時木の枝が私の頭に落ちた。
mori no naka de sanpo shite iru toki ki no eda ga watashi no atama ni ochita
forest GEN middle at stroll do-IMPF time tree GEN branch SUBJ 1s GEN head LOC fall.PST

[DanH34]

I was walking in the forest when a branch fell on my head.

Zidhgebzhail

vy ngoustidzadwouth gAmdzhaed haam bonsjam-vae ngoustens gAismien-iv

Spoiler:

v-y ngoust-idz-ad-wouth g-Amdzhae-d h-aam bons-jam-v-ae ngoust-ens-Ø g-Aismie-n-iv
1-ABS.SG.M tree-place-great-INESSIVE.SG.M PST-walk-PROG SUBORDINATOR-temporal_demonstrative head-SUPERLATIVE.SG.M-1-GEN.SG.M tree-piece-ABS.SG.M PST-fall-SIMPLE-INSTIGATIVE

I was walking in great-tree-place when onto my head tree-piece fell.

The instigative suffix 'iv' marks an anticausative verb when there is no causative noun-phrase within the clause. So, effectively, the branch fell without a cause.

Dan

[thetha]

Navajo
Tsintahdi naashá ńt’ę́ę́’go tsin bigąą shitsiits’iin bik’iikę́ę́z.
Forest-LOC to.move.about-1S.walk.IMPERF it.was-during tree 3S.POSS-arm 1S.POSS-head 3S.onto.3S-SSO.moves.independently

SSO= stiff, slender object (e.g. metal bar, walking stick)

[Selinki]

Selinki
Je rondevidaol sony gko eksja noravidaole jage kaczy
[je ronDeviD"a:ol s"o:n} G\o "eksja noraviD"a:ole j"a:ge kats`"}:]
I walk-PST-1SG forest-LOC when branch fall-PST-3SG my head-LOC

[MrKrov]

Pag-buum
Esk ŋam baid nim jeeŋ baid ja̤v bid muis ver nim wuh ŋam.
/esk ŋam baid nim ɖ͡ʐeːŋ baid ɖ͡ʐəv bid muis ver nim wux ŋam/
walk I be.at DEF forest be.at time fall branch go.to DEF head I
I was walking in the forest when a branch fell on my head.

[Imralu]

Swahili:

Nilikuwa nikitembea msituni (wakati) tawi lilipoanguka kichwani mwangu.
ni-li-ku-w-a ni-ki-tembe-a msitu-ni (wakati) tawi li-li-po-anguk-a kichwa-ni mw-angu
1s-PST-EXT-be-Ø 1s-SIT-walk-Ø forest-LOC (time(11)) branch(5) 5-PST-16.REL-fall-Ø head-LOC 18-GEN.1s
I was walking in the forest when a branch fell on my head.

[Threr]

Deyryck

èjlosa ni zladavûlaa'
forest POST-S:time head+branch+GOAL:none
I was walking in the forest when a branch fell on my head.

[Iyionaku]

Yélian

Yibernai iu rapar èpabetál prénabar yidenviet pas reo bobas.
[ɕɨˈbeɾnaɪ̯ ɪʊ̯ ˈɾaːpad̟ ˌɛpɐbəˈtaːl ˈpreːnɐbɐd̟ ɕɨˈdenvɪ̯ə̆‿pɐs ˈɾe.o ˈboːbɐʃ]
PST-walk-1SG through forest and_then branch PST-fall-3SG on 1SG.POSS head
I was walking in the forest when a branch fell on my head.

Caelian

Rar rapjagerek tibyäi tyer diz mi pigden korvosel Rabyes sitübdir.
[rah rapjagɛˈrɛk tʰiˈbʲæɪ̯ tʲɛɾ dis mi pʰigˈdɛn kʰɔɾvɔˈʒɛl ɾaˈbʲɛʃ ʒitʰybˈdiɾ]
1SG.NOM forest.PERL-ABL PPST-COP.1SG>3SG when so INDEF.NEUT branch.NOM head.SUBL 1SG.GEN-SUBL PST-fall.3SG>3SG
I was walking in the forest when a branch fell on my head.

Ular

我得森中去去着有我， 就上头我方蜢下有支一。
Lăn tā vāj ngû lhùlhù mŏn jù lăn, thŭ rhâ thā lăn vũ ngâjwō jù mú ów.
[lɛn˧˩ tɛ˧ ʋɑj˧ ŋu˧˥ ʟu˩ʟu˩ mɔn˩ ju˩ lɛn˩, tʰy˧˩ ra˧ tʰɛ˧ lɛn˧˩ ʋu˧ ŋaɪ̯˧˥ʊ̯ɔ˧ ju˩ mu˥ ɔʊ̯˥]
1SG TOP forest right_through walk_gently IMPF PST 1SG, when TOP head 1SG upon fall PST branch one
I was walking in the forest when a branch fell on my head.

Bath'aso

Zhuts shtumob pħor tħennzelizh shext homz ktrig bruzok kpultřokbo.
[ʐut͡s ˈʂtumɔb pˤʌɾ ˈtˤɛnːzɛliʐ ʂɛxt hɔmz ͡ktrig ˈbruzɔk ͡kpɯltr̟ɔkbʌ]
CONT walk=1SG.ABS in forest-likeable-INDR RESULT fall branch.ABS onto head-worry.ABS=1SG.GEN
I was walking in the forest when a branch fell on my head.

Paatherye

सा त्षिड़़ ऊतिं व्वीढर कैसी ओकु, षूते सें त्रौपेज़ यें पेरलू फो नेयाहे स्रौहेज़.
Sā tșiran ūtim vīdhar kaysī ēku, șūte sem treybes yem perlū phē neyāhe sreyhes.
[saː ˈtʃiran ˈuːtim ˈviːθar ˈkaɪ̯siː ˈeːku, ˈʃuːte sem ˈtrei̯bes jem ˈpeɾluː pʰeː neˈjaːhe ˈsɾei̯hes]
INDEF.FEM.ACC roundway.ACC in=DEF forest.LOC perform.IPF.1SG 1SG.NOM, when INDEF.MASC.NOM branch AUX.AOR.3SG.MASC fall.PP on 1SG.POSS.FEM.ALL head.ALL
I was walking in the forest when a branch fell on my head.

[Alessio]

Italiano
Stavo camminando nella foresta quando mi è caduto in testa un ramo.
/stavo kammi'nando nella fo'rεsta 'kwando mj‿ε ka'duːto in 'tεsta un 'raːmo/
st-avo cammin-ando ne-lla foresta quando mi è cad-ut-o in testa un ramo
PROGR-1SG.IMPF walk.GER in-DET.FS forest when 1SG.DAT be.3SG fall-PART.PASS-M in head INDEF.M branch

As you can see, "in head" is used for "on the head" (straight out of Latin!), and you do not say that a branch fell on your head, but rather than a branch fell "to you on the head".

Emilian - Dialàt Vgnulěṡ (specific dialect of an Italian local language)
A-j-ěra a drě ch'a andêva par la furěsta, pò d'impruvîṡ a m'è caschê na brôca in těsta.
/ɐjeːr‿a dreː k‿andεːvɐ pɐr lɐ fʊ'reːstɐ pɔ dɪmprʊ'viːz ɐ mε kɐs'kεː nɐ 'brɔkɐ ɪn 'teːstɐ/
a (j) ěr-a a_drě ca a and-êva par la furěsta pò d'impruvîṡ a m è casch-ê na brôca in těsta
1SG (euphonic) be.IMPF-1SG PROGR that 1SG go-IMPF.1SG through DET.FS forest then suddenly 3SG 1SG.DAT be.3SG fall-PART.PASS INDET.F branch in head

Notice how the pronouns for 1SG and 3SG are the same. Normally the 3SG pronoun would be "al", but when the noun it stands for is explicit (brôca in this case), a pronoun before the verb is still necessary but it is reduced to "a". Also, I'm not quite sure why "brôca" is feminine but it's considered masculine in "a m'è caschê" (you'd use "caschêda" for feminine nouns normally). It's probably related to "a m'è caschê" being some sort of dative construction. Finally... yeah, the Emilian word for when ("quand" /kwãː(n)d/) isn't really used in sentences like this one. You'd normally just go with ", pò" (", then"), to which I added "d'impruvîṡ" (suddenly) so that it would not be too distant in time.

[Lao Kou]

Géarthnuns

Zçeshtanö sí lé cha hansav nzdanez sho, sö çörebs lé chí öçalsíb deçe vürwaz.
while 1SG-NOM AUX.PAST DEF forest-LOC walk PTCL, INDEF branch-NOM AUX.PAST DEF head-POST onto fall
I was walking in the forest when a branch fell on my head.

---

Japoné語

私 oué quand j'ga 散歩ététa dans la 森 dé, une 枝 oué ça ga 落tchita sur mon 頭 ni.
Ouétachi oué quand j'ga sampauététa dans la maurie dé, une éda oué ça ga otchita sur mon atama ni.
1SG TOP when 1SG=NOM walk-PROG.PAST in DEF forest LOC, INDEF branch TOP 3SG NOM fall-PAST on my head ALL
I was walking in the forest when a branch fell on my head.

[Dormouse559]

French
Je me promenais dans la forêt quand une branche m'est tombée sur la tête.
/ʒ‿mə pʁɔ.mnɛ dɑ̃ la fɔ.ʁɛ kɑ̃.t‿yn bʁɑ̃ʃ me tɔ̃.be syʁ la tɛt/
1SG.NOM 1SG.REFL walk-IPF{1SG} in DEF-F forest when INDEF.F branch 1SG.DAT=be.3SG fall-PST_PTCP{F} on DEF-F head

Silvish
Jou me parmenö dent lui fouêtte canca me se czû en-a brance su lui têtte.
[ʑu.me.paʁ.məˈnøː dɛ̃l.lɥiˈfwet.tə kɑ̃.ka.me.səˈɕyː ẽ.əˈbʁɑ̃.ɕə sy.lɥiˈtet.tə]
1SG.NOM 1SG.REFL walk-IPF.1SG in DEF-OBL forest.OBL when 1SG.DAT=3SG=be.3SG fall-PST_PTCP.F INDEF-F.NOM branch on DEF-OBL head.OBL

Romanglic
During ego's forest promenade, arboreal member plummeted, encountering ego's cranium.

[Reyzadren]

griuskant (without the conscript)

aesk yurda vuzh hilsek vozh yelk shrodant ki aeskae rauk.
/esk 'jurda vuʒ 'hilsək vɔʒ 'jəlk 'ʃrɔdant ki eske 'rauk/
1SG walk-V at forest during branch fall-V-PASS-PST to 1SG-POSS head

[qwed117]

r·nhat a·hràid ġaa śè hr·dwààn mhààg ta·sahl mh·ga ġaa sa·sàwid hri·ñuu
IPFV walk 1SG LOC forest SML head GEN 1SG fell branch
I was walking in the forest when a branch fell on my head

The semelfactive here is being used as a conjunction, something like "once" almost (except "when")