からして

1. 1Judging from X; names a clue or basis from which the speaker draws an inference.Ex. 1
2. 2To begin with X, even X; one representative item shows that the rest is similar, typically negatively.Ex. 3

Common in both speech and writing. The judging sense is often followed by inference expressions such as ようだ, らしい or 伺える. Compared with からすると / からすれば, からして points more sharply to one telling clue. It also has the extra "even X, to begin with" sense, which usually introduces a critical remark.

• 1.
  からすると / からすればN2When expressing a basis for inference, the two are often interchangeable, but 「からして」 more strongly emphasizes that this one point alone is enough to draw a conclusion. 「からすると」 can also mean 'from someone's or some standpoint's perspective' (e.g. 「親からすると」), but it has no 'if even X is..., then...' analogical meaning.
• 2.
  から見るとN2「から見ると」 is close to 「からして」 only in the sense of 'judging from / inferring from', and the two are often interchangeable. It can also mean 'in someone's view', but it has no 'if even X is..., then...' analogical usage.
• 3.
  から言うとN2「から言うと」 attaches to nouns of standpoint or viewpoint—angles of judgment—and makes an evaluation from that angle; the first sense of 「からして」 attaches to concrete signs such as attitude or appearance to make an inference. 「からして」 has a second sense, 'if even X is..., then...', which 「から言うと」 lacks.
• 4.
  ところからN2「ところから」 can attach to verbs, adjectives, and noun + である, and has a strong literary flavor. It is often used to explain the origin of a name or a result drawn from a fact, and the second clause must be an objective result or judgment; it has no 'if even X is..., then...' analogical meaning.
• 5.
  こそN3「こそ」 emphasizes that the preceding item is 'precisely the one', often with a tone of contrast with others, and does not extend from it to the rest; 「からして」, by contrast, uses it as a basis to infer or generalize to the whole. 「こそ」 can also attach to case particles, the て-form, and more, so the two cannot be interchanged.
• 6.
  さえN3「さえ」 is close only to the second sense of 「からして」: 「さえ」 gives an extreme example meaning 'even...', often pairing with negatives, while 「からして」 extends from the most basic item to the whole and can be either positive or negative. 「さえ」 can also attach to case particles and verbs, and has an additional meaning of 'in addition'.

からすると / からすれば and から見ると also mean "judging from" or "from the viewpoint of," but they can state a person's standpoint and lack からして's "even X" sense. から言うと states the standpoint used for an evaluation, ところから gives a basis expressed by a clause, こそ emphatically singles out X as "precisely X" (in positive or negative statements alike, e.g. 彼こそ犯人だ), and さえ means "even" without からして's nuance of "starting from X, so everything else follows."