In some sense, you can say なら is a subtype of ば. なら is ならば in its full form, and although this word makes no sense in modern Japanese, it did in olden times. Classical ならば is but a regular inflection of なり + ば, which rightly corresponds to today's であれば (である + ば).
So we can see that なら（ば） and ば don't really have differences in their meaning as conditionals, ...
I think it's definition #8 of the 助動詞(auxiliary verb) "た" in デジタル大辞泉:
たら is its 仮定形(hypothetical form). When used at the end of a sentence it indicates a suggestion, recommendation or advice, ...
The most concise explanation would be:
A なら B means "if there is an A, there is a B"
A たら B means "if A is completed, B happens"
なら doesn't really care about the time order. B could take place before, while, after doing A, or all time during A. It just tells "an A must be accompanied by a B". In linguistic jargon, なら makes aoristic condition.
Two common ways of translating "if and only if" use the terms 必要十分条件 ("necessary and sufficient condition") and 同値 ("equivalence").
a > b は式 (15) である為の必要十分条件である。
Equation (15) holds if and only if a > b.
式 （15） と「a>b」とは同値である。
Equation (15) is equivalent to a > b.
First, なきゃ is a contraction of なければ:
What is the meaning of りゃ in this phrase?
Meaning of 話になんない
Second, the literal, primary meaning of なきゃ/なけりゃ/なければ is "if not".
なければ often comes at the end of sentences, and that means the following part is omitted. What is omitted depends on the context.
(Unless ...,) something bad may happen. ⇒ One has to do ...
lit. Disturbing someone is bad
lit. If/should it disturb(s) someone, it is bad
の is but a nominalizer, while ては is a conditional expression. You can translate the latter as "disturbing someone is bad" in some situations too, but the two are different in principle. Maybe a better translation is "I'm afraid of disturbing ...
なくば is an older form of なければ. It's not generally used in modern Japanese (outside of perhaps a few fossilised expressions like さもなくば), but is still recognised and can be used as part of an affected style of speech.
This character's speech is clearly somewhat archaic in flavour (as also evidenced by the use of そなた and the ぬ negation), so the use of なくば seems ...
I would interpret them as...
"When I rested, I got better."
"When I read a book for my little brother, he was delighted."
(In these examples, the たら verb happened and caused the main verb)
If I wanted to say:
"If I had rested, I would have gotten better."
"If I had read a book for my little brother, he would ...
Neither is common. In fact, 戦いませば and 戦いますれば are almost never used in modern Japanese. You have to use 戦いましたら.
I sometimes hear stereotyped samurai in samurai dramas say 戦いますれば. It's indeed "if (someone) fights" said in a polite way. It's "stereotyped samurai-ish speech", but I don't know whether old people actually talked like this. People never use it ...
Here are the original lyrics:
The から in the first line simply means "because", and the first line works as the reason for the second line. "Because I will ride the first train when dawn breaks, please arrange a ticket (for me)." or "I will ride the first train when dawn ...
③ […] 引き続いて起こる事柄についての，きっかけを表す。…すると。
If I may add more to the quoted definition, this is a particular type of 〜ば where it denotes the chronology of a single occurrence (trigger event → following event), and says nothing about what would happen if the trigger event were to happen again. To me, this kind of 〜ば seems more common in ...
How certain is たら?
This question reads like asking, "How certain is if in English?" Nobody can tell exactly unless they know the full context. Also, it depends on what you say. If you say something like,
If (when) tomorrow comes, let's go on a picnic.
Is there any chance that there will be no tomorrow? Yes, if a ...
You are thinking of なくちゃ as must, but it's really just a contraction of なくては. なくてはならない and なくてはいけない are used to mean "must", and sometimes the final verb is dropped and なくちゃ by itself is used as a very casual way to imply that something must be done.
However, especially in cases where something comes after the なくちゃ, it can just mean なくては. See Jisho's ...
You're right. The ～～なければ here is a shortened form of ～～なければならない and means "have to~~" "should~~". And 清らかな子供たち, それを無条件で愛する教師, and 尊敬すべきこのクラス are the objects of 信じなければならない. (This is an inversion/倒置 of 清らかな子供たちと、それを無条件で愛する教師、尊敬すべきこのクラスを、信じなければ。)
They're so different that I've never thought those two words same. I think you're fooled by the English definition because "to the extent" can certainly cover both use cases to some extent. What they really mean are:
ほど "level" → ～ほど "to the (enough) level that — / according to how much —"
かぎり "limit" → ～かぎり "to ...
Edited in bold font
An action in non-past tense in a なら clause is to succeed that of the main clause, and if you use it wrongly, people will misunderstand which happens before and which after. Past tense in なら clauses stands for if it's true or not.
As long as you use なら correctly, たら is enough versatile to replace ～と and ～ば.
You can't use たら for actions in ...
Has this got two opposing meanings, or is it simple less-specific (or specific in another way) compared to English? We could express the meaning as:
when cheap → buy
If we turn to the English expressions, we find they both include this basic meaning:
counter-factual: when cheap → buy; but alas it's not cheap unfortunately
factual: when ...
if and only if (= iff)
a > b の時、（そして／かつ）その時に限り等式が成立する。
The equation is satisfied if and only if a > b.
only ... if
～なければ～ない (colloquially ～なきゃ～ない or ～なけりゃ～ない)
I'll only go if you buy me an ice.
The plant will only grow if it is watered regularly.
The difference between them ...
In addition to Marc Adler's explanation:
～と言ってたら is used as subjunctive past perfect. For example:
-- If I had said "I love you" at that time, we would be married now.
言ったら means "if I said(say)" or "I said ～ and then".
-- If I said(say) "I ...
Your translation attempt looks already perfect to me, but if you want to translate even more literally, you can say:
こと after a verb is a nominalizer, which turns verbs into nouns, like -ing in English. で is the particle which corresponds to by or for in this case.
Optionally you can also say:
The と in 言い換えてみると is not a quotative particle, but a conjunctive particle (接続助詞) meaning "When~" or "If~".
「言い換えてみると、・・・」 = "If/When you rephrase it, ..." "If/When you say it in a different way, ..."
「(Original Sentence)」を言い換えてみると、→ 「(Rephrased Sentence)。」
"If you rephrase / To rephrase '[Original Sentence]': (you'll get) '[...
The short answer
No, you can't say dekiba. Or rather, you could indeed say that, but it's not correct and folks might not catch your intended meaning. :)
The long answer
Dekiru is a so-called "type-2" or "vowel-stem" verb, where the stem of the vowel (the part that doesn't change when conjugating the different forms) ends in a vowel: dekiru → dekinai, ...
As the above, もし itself is a word like "excuse me". However, it ideomatically functions as an indicator that tells that a conditional clause follows next, which helps you comprehend what otherwise wouldn't be revealed until the last conjugation.
The same thing can be said about あまり、別に、何も (adverb) for ...