TipSome words, such as the Sena word kang'ombe, use apostrophes as word-forming characters. However, not all apostrophes can be used as word-forming characters. Language Explorer (FLEx) uses the Unicode properties for characters to decide which apostrophes are simply punctuation. This is crucial towards allowing FLEx to correctly find wordforms when it processes a text. Specifically, an incorrect apostrophe entered in a Baseline tab will cause that single word to appear as two words in the Gloss and Analyze tabs, such as kang and 'ombe from kang'ombe. As long as FLEx can correctly find the wordforms, then the parsers will see correct wordforms, not partial wordforms.
Use U+0027 APOSTROPHE or 02bc MODIFIER LETTER APOSTROPHE for the word-forming apostrophe rather than 2019 Right Single Quote mark.
02bc MODIFIER LETTER APOSTROPHE is defined as word-forming in the Unicode Standard so its use would be appropriate, but it has disadvantages:
Not all fonts include this code point. For example, Times New Roman does not (on systems that do not have Windows® 7/8/10, or Office 2007 or later), but Doulos SIL and Charis SIL both include it. So, as long as you use either of those fonts or another font that you know includes it, 02bc would work.
You will need a MSKLC (Microsoft Keyboard Layout Creator) or a Keyman keyboard to enter any 02bc characters.
If you already have a special keyboard, adding this (02bc) probably would not be too hard. Otherwise, use 0027 APOSTROPHE. This does not have the rounded appearance, but it is available in all fonts and does not require anything special to enter it.
TipIn Microsoft Word, you can disable the smart quote capability so it will enter 0027 instead of converting it to 2019 as you type.
You can examine the apostrophes discussed above in the Character Map.
You should reserve 2018 Left Single Quote mark and 2019 Right Single Quote mark for use as real quotation marks.
If you really need to use 2019, add it to the list of valid characters.
(Adapted from: https://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=EncodingFAQ)
If you want something that looks like a curly quote you should use U+02BC MODIFIER LETTER APOSTROPHE. You could use 2019 RIGHT SINGLE QUOTATION MARK, but there are at least two issues with that. It is considered punctuation with different properties than an orthographic character and if you use quote marks there is nothing to distinguish between the two characters. (Our Roman fonts (Doulos SIL, Charis SIL, Andika Basic and Gentium Basic) all have an alternate glyph for 02BC MODIFIER LETTER APOSTROPHE which is a bit larger than normal to help distinguish the glyph from 2019 RIGHT SINGLE QUOTATION MARK.)
Many orthographies have used something that looks like the straight quote. There were so many problems with using 0027 APOSTROPHE for this character that we requested the addition of a character to Unicode for that. You should use A78C LATIN SMALL LETTER SALTILLO (one language even "cases" this and A78B is used for the uppercase). (Our Roman fonts (Doulos SIL, Charis SIL, Andika Basic and Gentium Basic) all have an alternate glyph for A78C LATIN SMALL LETTER SALTILLO and A78B LATIN CAPITAL LETTER SALTILLO which are a bit larger than normal to help distinguish the glyph from 0027 APOSTROPHE.)
02BE MODIFIER LETTER RIGHT HALF RING is sometimes used for transliterating Arabic hamza (glottal stop). This looks different from both A78C LATIN SMALL LETTER SALTILLO and 02BC MODIFIER LETTER APOSTROPHE and might be a good option for traditions which recognize the transliterated hamza.
Some Saskatchewan orthographies use an upper and lowercase glottal stop. Those are 0241 LATIN CAPITAL LETTER GLOTTAL STOP and 0242 LATIN SMALL LETTER GLOTTAL STOP.
Of course, the IPA representation is 0294 LATIN LETTER GLOTTAL STOP and some languages also use this in their orthographies (where casing is not required).