Because, so and the connector gaw

The sentence that rewires you fastest is เพราะฝนตก ก็เลยไม่ได้ไป (phráw fǒn dtòk gâw loei mâi dâi bpai): because it rained, so I didn't get to go. English forces you to choose one connector, because or so, never both; Thai happily marks the cause at one end and the result at the other, and nobody hears it as redundant. The second thing to absorb is which half does the real work. In everyday speech Thais very often drop เพราะ entirely, state the cause bare, and hang the result on ก็เลย (gâw loei): รถติดมาก ก็เลยมาสาย (rót dtìt mâak gâw loei maa sǎai), traffic was bad, so I came late. If your textbook only gave you เพราะ, this is the upgrade. เพราะ (phráw) is because, and it attaches directly to a reason: เพราะอากาศดี (phráw aa-gàat dii), because the weather is good. เพราะว่า (phráw wâa) means exactly the same; the ว่า is the same clause-opener you know from บอกว่า (bàwk wâa, say that) and คิดว่า (khít wâa, think that), so it signals that a full sentence of explanation is coming. That makes เพราะว่า the natural way to open an answer to ทำไม (tham-mai, why): ทำไมไม่กิน, why aren't you eating, gets เพราะว่าเผ็ดเกินไป (phráw wâa phèt goen bpai), because it's too spicy. In fast speech the answer often starts ก็เพราะว่า, the ก็ just cushioning the launch. ก็เลย has a fixed home: inside the result clause, after the subject, before the verb. ฝนตก ผมก็เลยอยู่บ้าน (fǒn dtòk phǒm gâw loei yùu bâan), it rained, so I stayed home. It never floats at the front of the whole sentence the way English 'So, ...' does; when a Thai sentence seems to begin with ก็เลย, the subject has simply been dropped, which Thai does constantly. เลย alone is the lighter, more casual version and slots into the same place: เลยไม่ได้ไป (loei mâi dâi bpai). Order matters absolutely: cause first, then ก็เลย plus result. You cannot lead with the result the way English can; if the result has to come first, you switch tools and trail the reason with เพราะ: อยู่บ้านเพราะฝนตก (yùu bâan phráw fǒn dtòk). Why does Thai double-mark at all? Because ก็ is the language's all-purpose hinge between two connected ideas, and Thai likes both sides of a link labelled. You already see the pattern in ถ้าฝนตก ก็ไม่ไป (thâa fǒn dtòk gâw mâi bpai), if it rains, then I won't go, and in พอถึงบ้าน ก็โทรหานะ (phaw thěung bâan gâw thoo hǎa ná), once you get home, then call me. If-then, when-then, because-so: the second clause gets a ก็. Stop resisting it as redundant and your sentences immediately sound more Thai. Now the formal shelf, which you need for signs, announcements and official letters rather than for your own mouth. ดังนั้น (dang-nán) is therefore; its partner จึง (jeung) is the written cousin of ก็เลย and sits in the same pre-verb slot: ดังนั้นจึงขอปิดให้บริการชั่วคราว, therefore we are temporarily closed. เนื่องจาก (nêuang-jàak), owing to, is the formal เพราะ and opens announcements: เนื่องจากฝนตกหนัก, owing to heavy rain. Between the registers sits เพราะฉะนั้น (phráw chà-nán), so then, that being the case, which is completely normal in speech; teachers and bosses use it constantly. In genuinely casual speech เพราะฉะนั้น shrinks to เพราะงั้น (phráw ngán), and most often to bare งั้น (ngán), in that case, then: งั้นเจอกันพรุ่งนี้นะ (ngán joe gan phrûng-níi ná), in that case see you tomorrow. งั้น answers the situation itself rather than a stated cause, which is why it can open a sentence when ก็เลย cannot; it is how plans get settled at the table. And จึง has a spoken twin, ถึง (thěung), sitting in the same pre-verb slot. You meet it inside why-questions: ทำไมถึงมาเมืองไทย (tham-mai thěung maa meuang-thai), why is it that you came to Thailand, and in answers that echo it: ฝนตก รถถึงติด (fǒn dtòk rót thěung dtìt), it rained, that is why traffic jammed. The whole map is small: reasons are เพราะ and เพราะว่า in conversation, เนื่องจาก formally; results are เลย, ก็เลย and ถึง in conversation, งั้น and เพราะฉะนั้น to move a conversation forward, จึง and ดังนั้น formally. Learn these and you are done collecting. That leaves ก็ (gâw) itself, the most Thai word there is and the one no dictionary translates well. Its core job is linking: it tells the listener that this sentence leans on the one before it. With a repeated idea it means too or either: someone says they don't know, and you answer ผมก็ไม่รู้ (phǒm gâw mâi rúu), I don't know either. Stringing actions it means then: กินข้าว แล้วก็อาบน้ำ (gin khâao láew gâw àap náam), eat, and then shower. แล้วก็ (láew gâw) is the everyday 'and then, and also' that holds any spoken list together. ก็ is also Thai's 'well...', a hesitation that softens whatever follows. เป็นยังไงบ้าง (bpen yang-ngai bâang), how's it going, answered with ก็ดีนะ (gâw dii ná), well, it's alright. Hear the difference: ดีมาก is enthusiastic, ก็ดี is lukewarm, 'okay I guess', and sometimes polite cover for 'not great'. Thai culture prefers cushioned answers to blunt ones, and ก็ is the cheapest cushion in the language. When someone starts a reply with a long drawn-out ก็..., they are composing a diplomatic answer; give them a moment, and take the softened reply seriously. Question word plus ก็ได้ (gâw dâi) turns any question word into 'any X at all', literally 'even X is possible'. The set is closed, so take all of it: อะไรก็ได้ (à-rai gâw dâi) anything, ใครก็ได้ (khrai gâw dâi) anyone, ที่ไหนก็ได้ (thîi-nǎi gâw dâi) anywhere, เมื่อไหร่ก็ได้ (mêua-rài gâw dâi) anytime, ยังไงก็ได้ (yang-ngai gâw dâi) any way works, อันไหนก็ได้ (an-nǎi gâw dâi) whichever one, เท่าไหร่ก็ได้ (thâo-rài gâw dâi) any amount, whatever it costs, กี่โมงก็ได้ (gìi moong gâw dâi) any time of day, วันไหนก็ได้ (wan nǎi gâw dâi) any day. The last three run your life admin: เท่าไหร่ก็ได้ when quantity does not matter, กี่โมงก็ได้ and วันไหนก็ได้ when the clinic receptionist asks when you can come in. Asked which noodles you want, อะไรก็ได้ครับ ends the negotiation pleasantly. After a verb or a whole proposal, ก็ได้ is easy agreement: ไปก็ได้ (bpai gâw dâi), sure, going works; พรุ่งนี้ก็ได้ (phrûng-níi gâw dâi), tomorrow is fine too. Respect the nuance: ก็ได้ says 'that option is acceptable', not 'I love it'. Said warmly, with ครับ or ค่ะ attached, it is easy-going and gracious, the sound of someone pleasant to make plans with. Said flat, it is the Thai teenager's 'fine, whatever', and Thai ears catch the reluctance instantly. When you actually like the plan, say ดีเลย (dii loei), great, or เอาสิ (ao sì), let's do it, and keep ก็ได้ for when you genuinely mean 'either way suits me'. One last disambiguation, because เลย has three jobs and only one of them is 'so'. Pre-verb in a result clause it is the ก็เลย you now own. Sentence-final it intensifies: อร่อยมากเลย (à-ràwy mâak loei), really delicious; after a negative it means 'at all': ไม่แพงเลย (mâi phaeng loei), not expensive at all. And as a verb it means to go past: เลยไฟแดงไปหน่อย (loei fai daeng bpai nàwy), a bit past the red light, which you will say to taxi drivers weekly. Position tells you which เลย you are hearing. Your homework this week is one shape: state the cause plainly, then ก็เลย plus what happened, every time you explain yourself to the landlord, the pharmacist or the immigration officer. It is the single highest-mileage pattern in spoken Thai.