tu-

While tu- usually starts the verb, there are a few important structural rules to become comfortable with:

• Before Vowels and the -a- Tense: Generally, tu- remains unchanged before verb roots starting with a vowel (e.g., tuanze = let's start, tuimbe = let's sing), though contracted forms like twanze are also acceptable variants. For the verb kwenda (to go), the subjunctive form is twende (let's go). This is a result of vowel coalescence (tu- + -end- + -e = twende), a standard phonological rule, though modern Swahili often resists this glide in other verbs. Additionally, when tu- combines with the present indefinite tense marker -a-, it becomes twa- (e.g., tu- + -a- + -soma = twasoma, meaning 'we read'). Note that while twasoma is grammatically correct and used in literary or regional contexts, the present tense marker -na- (e.g., tunasoma) is much more common in everyday spoken Swahili for both 'we are reading' and 'we read'.
• With Basic Tenses: tu- combines regularly with standard tense markers like the Past -li- (e.g., tulisoma = we read) and the Perfect -me- (e.g., tumesoma = we have read).
• With Object Markers: When using an object marker to indicate who or what is receiving the action, the object infix sits directly between the tense marker (or the subject marker in the subjunctive) and the verb root. For example, tutamsaidia (we will help him/her) or tumsaidie (let's help him/her).
• With Relative Infixes: When saying 'we who...', the relative pronoun infix attaches directly after the tense marker in present and past affirmative clauses. For example, tunaosoma (we who are reading), where -o- is the Class 2 Relative -o- referring to 'us'. However, for the future tense, the marker -ta- changes to -taka- (e.g., tutakaosoma = we who will read). The perfect tense marker -me- cannot take a relative infix at all; instead, you must use the independent relative word ambao (e.g., sisi ambao tumesoma = we who have read). In tenseless relatives, the infix attaches to the end of the verb (e.g., tusomao = we who read), and in negative relatives, it attaches directly to the negative marker -si- (e.g., tusiosoma = we who do not read). Alternatively, a very common approach in everyday speech is to use the independent relative word ambao (e.g., sisi ambao tunasoma = we who are reading).
• Negation: When saying 'we do not', the negative marker ha- comes before the subject marker, creating hatu-. For example, We Do Not hatu- (hatusomi = we are not reading). Note that changing the final vowel to -i only applies to the present tense of native verbs ending in -a. Borrowed verbs ending in other vowels keep their final vowel (e.g., hatujibu = we do not answer). In many other tenses, you still use hatu- but the verb keeps its normal ending. For example, in the past tense, the tense marker changes from -li- to -ku- (e.g., hatukusoma = we did not read), the future tense keeps -ta- (e.g., hatutasoma = we will not read), and the perfect tense marker -me- changes to -ja- (e.g., hatujasoma = we have not yet read). However, conditional tenses (like -nge- and -ngali-) and the -ki- tense do not use hatu-. Instead, they use the negative infixes -si- (e.g., tusingesoma = we would not read) and -sipo- (e.g., tusiposoma = if we do not read). For monosyllabic verbs like kula (to eat), the infinitive ku- is dropped in the present negative (e.g., hatuli = we do not eat). Crucially, for monosyllabic verbs in the past negative, the infinitive ku- is dropped in Standard Swahili to avoid repeating -ku- (e.g., hatukula = we did not eat). However, in Kenyan Swahili, retaining the ku- (e.g., hatukukula) is very common.
• Subjunctive: When suggesting 'let us do something', tu- attaches directly to the verb root, skipping the tense marker entirely. For native verbs ending in -a, the final vowel changes to -e (tusome = let's read). Borrowed verbs keep their original ending (e.g., tujibu = let's answer). For monosyllabic verbs, the infinitive ku- is dropped (e.g., tule = let's eat). When rallying a group of more than one person, Swahili speakers commonly add the plural suffix -ni to the end of the verb (e.g., twendeni = let's all go). For the Negative Subjunctive, do not use the ha- prefix; instead, place the infix -si- right after the subject marker (e.g., tusisome = let's not read). For monosyllabic verbs, the infinitive ku- is also dropped here (e.g., tusile = let's not eat).
• Habitual Tense: In the Habitual hu- tense (meaning 'usually do'), subject prefixes like tu- are dropped entirely. You just use hu- plus the verb root. Because a word like husoma is subject-neutral and can mean anyone usually reads, you must add the independent pronoun to specify 'we' (e.g., Sisi husoma = we usually read). For monosyllabic verbs, the infinitive ku- is dropped (e.g., Sisi hula = we usually eat).

Be careful not to confuse it with:
1. The First-Person Plural Object -tu- ('us'). Note that the subject prefix and the object infix are identical in form (tu). However, the object marker goes inside the verb, right before the root (e.g., alituona = he saw us).
2. The word Only or Just with tu. This is a separate, free-standing word placed after a noun or verb (e.g., kidogo tu = just a little).